Assessment of commercially available energy-efficient room air conditioners including models with low global warming potential (GWP) refrigerants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shah, N. K.; Park, W. Y.; Gerke, B.

Improving the energy efficiency of room air conditioners (RACs) while transitioning to low global-warming-potential (GWP) refrigerants will be a critical step toward reducing the energy, peak load, and emissions impacts of RACs while keeping costs low. Previous research quantified the benefits of leapfrogging to high efficiency in tandem with the transition to low-GWP refrigerants for RACs (Shah et al., 2015) and identified opportunities for initial action to coordinate energy efficiency with refrigerant transition in economies constituting about 65% of the global RAC market (Shah et al., 2017). This report describes further research performed to identify the best-performing (i.e., most efficientmore » and low-GWP-refrigerant using) RACs on the market, to support an understanding of the best available technology (BAT). Understanding BAT can help support market-transformation programs for high-efficiency and low-GWP equipment such as minimum energy performance standards (MEPS), labeling, procurement, and incentive programs. We studied RACs available in six economies—China, Europe, India, Japan, South Korea, and the United States—that together account for about 70% of global RAC demand, as well as other emerging economies. The following are our key findings: • Highly efficient RACs using low-GWP refrigerants, e.g., HFC-32 (R-32) and HC-290 (R-290), are commercially available today at prices comparable to similar RACs using high-GWP HCFC-22 (R-22) or HFC-410A (R-410A). • High efficiency is typically a feature of high-end products. However, highly efficient, cost-competitive (less than 1,000 or 1,500 U.S. dollars in retail price, depending on size) RACs are available. • Where R-22 is being phased out, high GWP R-410A still dominates RAC sales in most mature markets except Japan, where R-32 dominates. • In all of the economies studied except Japan, only a few models are energy efficient and use low-GWP refrigerants. For example, in Europe, India, and Indonesia, the highest-efficiency RAC models employ the low-GWP refrigerants R-32 or R-290. • RACs are available in most regions and worldwide that surpass the highest efficiency levels recognized by labeling programs. • Fixed-speed RACs using high-GWP and ozone-depleting R-22 refrigerant still dominate the market in many emerging economies. There is significant scope to improve RAC efficiency and transition to low-GWP refrigerants using commercially available technology and to design market-transformation programs for high-efficiency, low-GWP equipment including standards, labeling, procurement, and incentive programs.« less

Design and experimental investigation of an ejector in an air-conditioning and refrigeration system

DOE Office of Scientific and Technical Information (OSTI.GOV)

AL-Khalidy, N.; Zayonia, A.

1995-12-31

This paper discusses the conservation of energy in a refrigerant ejector refrigerating machine using heat driven from the concentrator collectors. The working refrigerant was R-113. The design of an ejector operating in an air-conditioning and refrigerating system with a low thermal source (70 C to 100 C) is presented. The influence of three major parameters--boiler, condenser, and evaporator temperature--on ejector efficiency is discussed. Experimental results show that the condenser temperature is the major influence at a low evaporator temperature. The maximum ejector efficiency was 31%.

Thermal conductance measurements of bolted copper joints for SuperCDMS

DOE PAGES

Schmitt, R. L.; Tatkowski, G.; Ruschman, M.; ...

2015-04-28

Joint thermal conductance testing has been undertaken for bolted copper to copper connections from 60 mK to 26 K. This testing was performed to validate an initial design basis for the SuperCDMS experiment, where a dilution refrigerator will be coupled to a cryostat via multiple bolted connections. Copper used during testing was either gold plated or passivated with citric acid to prevent surface oxidation. Finally, the results we obtained are well fit by a power law regression of joint thermal conductance to temperature and match well with data collected during a literature review.

Refrigerated Warehouse Demand Response Strategy Guide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott, Doug; Castillo, Rafael; Larson, Kyle

This guide summarizes demand response measures that can be implemented in refrigerated warehouses. In an appendix, it also addresses related energy efficiency opportunities. Reducing overall grid demand during peak periods and energy consumption has benefits for facility operators, grid operators, utility companies, and society. State wide demand response potential for the refrigerated warehouse sector in California is estimated to be over 22.1 Megawatts. Two categories of demand response strategies are described in this guide: load shifting and load shedding. Load shifting can be accomplished via pre-cooling, capacity limiting, and battery charger load management. Load shedding can be achieved by lightingmore » reduction, demand defrost and defrost termination, infiltration reduction, and shutting down miscellaneous equipment. Estimation of the costs and benefits of demand response participation yields simple payback periods of 2-4 years. To improve demand response performance, it’s suggested to install air curtains and another form of infiltration barrier, such as a rollup door, for the passageways. Further modifications to increase efficiency of the refrigeration unit are also analyzed. A larger condenser can maintain the minimum saturated condensing temperature (SCT) for more hours of the day. Lowering the SCT reduces the compressor lift, which results in an overall increase in refrigeration system capacity and energy efficiency. Another way of saving energy in refrigerated warehouses is eliminating the use of under-floor resistance heaters. A more energy efficient alternative to resistance heaters is to utilize the heat that is being rejected from the condenser through a heat exchanger. These energy efficiency measures improve efficiency either by reducing the required electric energy input for the refrigeration system, by helping to curtail the refrigeration load on the system, or by reducing both the load and required energy input.« less

Heat pump with freeze-up prevention

DOEpatents

Ecker, Amir L.

1981-01-01

What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating the fluid in heat exchange relationship with a refrigerant fluid; at least two refrigerant heat exchangers, one for effecting heat exchange with the fluid and a second for effecting heat exchange between refrigerant and a heat exchange fluid and the ambient air; a compressor for efficiently compressing the refrigerant; at least one throttling valve for throttling liquid refrigerant; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and direction of flow of the refrigerant therethrough for selecting a particular mode of operation. The heat exchange fluid prevents freeze up of the second heat exchanger by keeping the temperature above the dew point; and, optionally, provides heat for efficient operation.

Optimal low symmetric dissipation Carnot engines and refrigerators

NASA Astrophysics Data System (ADS)

de Tomás, C.; Hernández, A. Calvo; Roco, J. M. M.

2012-01-01

A unified optimization criterion for Carnot engines and refrigerators is proposed. It consists of maximizing the product of the heat absorbed by the working system times the efficiency per unit time of the device, either the engine or the refrigerator. This criterion can be applied to both low symmetric dissipation Carnot engines and refrigerators. For engines the criterion coincides with the maximum power criterion and then the Curzon-Ahlborn efficiency ηCA=1-Tc/Th is recovered, where Th and Tc are the temperatures of the hot and cold reservoirs, respectively [Esposito, Kawai, Lindenberg, and Van den Broeck, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.105.150603 105, 150603 (2010)]. For refrigerators the criterion provides the counterpart of Curzon-Ahlborn efficiency for refrigerators ɛCA=[1/(1-(Tc/Th)]-1, first derived by Yan and Chen for the particular case of an endoreversible Carnot-type refrigerator with linear (Newtonian) finite heat transfer laws [Yan and Chen, J. Phys. D: Appl. Phys.JPAPBE0022-372710.1088/0022-3727/23/2/002 23, 136 (1990)].

76 FR 31951 - Energy Conservation Program for Certain Commercial and Industrial Equipment: Decision and Order...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-02

... specific to the Carrier Super Modular Multi-System (SMMSi) variable refrigerant flow (VRF) multi-split... in this notice to test and rate its SMMSi VRF multi-split commercial heat pumps. DATES: This Decision... its SMMSi VRF multi-split products. Carrier must use the alternate test procedure provided in this...

A combined power and ejector refrigeration cycle for low temperature heat sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, B.; Weng, Y.W.

A combined power and ejector refrigeration cycle for low temperature heat sources is under investigation in this paper. The proposed cycle combines the organic Rankine cycle and the ejector refrigeration cycle. The ejector is driven by the exhausts from the turbine to produce power and refrigeration simultaneously. A simulation was carried out to analyze the cycle performance using R245fa as the working fluid. A thermal efficiency of 34.1%, an effective efficiency of 18.7% and an exergy efficiency of 56.8% can be obtained at a generating temperature of 395 K, a condensing temperature of 298 K and an evaporating temperature ofmore » 280 K. Simulation results show that the proposed cycle has a big potential to produce refrigeration and most exergy losses take place in the ejector. (author)« less

Effects of hysteresis and Brayton cycle constraints on magnetocaloric refrigerant performance

NASA Astrophysics Data System (ADS)

Brown, T. D.; Buffington, T.; Shamberger, P. J.

2018-05-01

Despite promising proofs of concept, system-level implementation of magnetic refrigeration has been critically limited by history-dependent refrigerant losses that interact with governing thermodynamic cycles to adversely impact refrigeration performance. Future development demands a more detailed understanding of how hysteresis limits performance, and of how different types of cycles can mitigate these limitations, but without the extreme cost of experimental realization. Here, the utility of Brayton cycles for magnetic refrigeration is investigated via direct simulation, using a combined thermodynamic-hysteresis modeling framework to compute the path-dependent magnetization and entropy of a model alloy for a variety of feasible Brayton cycles between 0-1.5 T and 0-5 T. By simultaneously varying the model alloy's hysteresis properties and applying extensions of the thermodynamic laws to non-equilibrium systems, heat transfers and efficiencies are quantified throughout the space of hystereses and Brayton cycles and then compared with a previous investigation using Ericsson cycles. It is found that (1) hysteresis losses remain a critical obstacle to magnetic refrigeration implementation, with efficiencies >80% in the model system requiring hysteresis <0.5 K at 1.5 T; (2) optimal-efficiency Brayton cycles for given field and hysteresis constraints exist and are determined uniquely by the refrigerant transformation temperatures at the relevant fields; (3) for a given hysteresis and field constraint, Brayton and Ericsson-type cycles generate similar efficiencies; for a given temperature span, Ericsson cycles lift more heat per cycle, with the difference decreasing with the refrigerant heat capacity outside the phase transformation region.

Functional Dependence of Thermodynamic and Thermokinetic Parameters of Refrigerants Used in Mine Air Refrigerators. Part 1 - Refrigerant R407C

NASA Astrophysics Data System (ADS)

Nowak, Bernard; Życzkowski, Piotr; Łuczak, Rafał

2017-03-01

The authors of this article dealt with the issue of modeling the thermodynamic and thermokinetic properties (parameters) of refrigerants. The knowledge of these parameters is essential to design refrigeration equipment, to perform their energy efficiency analysis, or to compare the efficiency of air refrigerators using different refrigerants. One of the refrigerants used in mine air compression refrigerators is R407C. For this refrigerant, 23 dependencies were developed, determining its thermodynamic and thermokinetic parameters in the states of saturated liquid, dry saturated vapour, superheated vapor, subcooled liquid, and in the two-phase region. The created formulas have been presented in Tables 2, 5, 8, 10 and 12, respectively. It should be noted that the scope of application of these formulas is wider than the range of changes of that refrigerant during the normal operation of mine refrigeration equipment. The article ends with the statistical verification of the developed dependencies. For this purpose, for each model correlation coefficients and coefficients of determination were calculated, as well as absolute and relative deviations between the given values from the program REFPROP 7 (Lemmon et al., 2002) and the calculated ones. The results of these calculations have been contained in Tables 14 and 15.

Thermal conductance modeling and characterization of the SuperCDMS-SNOLAB sub-Kelvin cryogenic system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dhuley, R. C.; Hollister, M. I.; Ruschman, M. K.

The detectors of the Super Cryogenic Dark Matter Search experiment at SNOLAB (SuperCDMS SNOLAB) will operate in a seven-layered cryostat with thermal stages between room temperature and the base temperature of 15 mK. The inner three layers of the cryostat, which are to be nominally maintained at 1 K, 250 mK, and 15 mK, will be cooled by a dilution refrigerator via conduction through long copper stems. Bolted and mechanically pressed contacts, at and cylindrical, as well as exible straps are the essential stem components that will facilitate assembly/dismantling of the cryostat. These will also allow for thermal contractions/movements duringmore » cooldown of the sub-Kelvin system. To ensure that these components and their contacts meet their design thermal conductance, prototypes were fabricated and cryogenically tested. The present paper gives an overview of the SuperCDMS SNOLAB sub-Kelvin architecture and its conductance requirements. Results from the conductance measurements tests and from sub-Kelvin thermal modeling are discussed.« less

Krypton based adsorption type cryogenic refrigerator

NASA Technical Reports Server (NTRS)

Jones, Jack A. (Inventor); Schember, Helene R. (Inventor)

1989-01-01

Krypton and a monolithic porous carbon such as Saran carbon are used respectively as the sorbate and sorbent of an adsorption type refrigerator to improve refrigeration efficiency and operational longevity.

Thermal management and design for optical refrigeration

NASA Astrophysics Data System (ADS)

Symonds, G.; Farfan, B. G.; Ghasemkhani, M. R.; Albrecht, A. R.; Sheik-Bahae, M.; Epstein, R. I.

2016-03-01

We present our recent work in developing a robust and versatile optical refrigerator. This work focuses on minimizing parasitic energy losses through efficient design and material optimization. The cooler's thermal linkage system and housing are studied using thermal analysis software to minimize thermal gradients through the device. Due to the extreme temperature differences within the device, material selection and characterization are key to constructing an efficient device. We describe the design constraints and material selections necessary for thermally efficient and durable optical refrigeration.

Benefits of Leapfrogging to Superefficiency and Low Global Warming Potential Refrigerants in Room Air Conditioning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shah, Nihar; Wei, Max; Letschert, Virginie

2015-10-01

Hydrofluorocarbons (HFCs) emitted from uses such as refrigerants and thermal insulating foam, are now the fastest growing greenhouse gases (GHGs), with global warming potentials (GWP) thousands of times higher than carbon dioxide (CO2). Because of the short lifetime of these molecules in the atmosphere, mitigating the amount of these short-lived climate pollutants (SLCPs) provides a faster path to climate change mitigation than control of CO2 alone. This has led to proposals from Africa, Europe, India, Island States, and North America to amend the Montreal Protocol on Substances that Deplete the Ozone Layer (Montreal Protocol) to phase-down high-GWP HFCs. Simultaneously, energymore » efficiency market transformation programs such as standards, labeling and incentive programs are endeavoring to improve the energy efficiency for refrigeration and air conditioning equipment to provide life cycle cost, energy, GHG, and peak load savings. In this paper we provide an estimate of the magnitude of such GHG and peak electric load savings potential, for room air conditioning, if the refrigerant transition and energy efficiency improvement policies are implemented either separately or in parallel. We find that implementing HFC refrigerant transition and energy efficiency improvement policies in parallel for room air conditioning, roughly doubles the benefit of either policy implemented separately. We estimate that shifting the 2030 world stock of room air conditioners from the low efficiency technology using high-GWP refrigerants to higher efficiency technology and low-GWP refrigerants in parallel would save between 340-790 gigawatts (GW) of peak load globally, which is roughly equivalent to avoiding 680-1550 peak power plants of 500MW each. This would save 0.85 GT/year annually in China equivalent to over 8 Three Gorges dams and over 0.32 GT/year annually in India equivalent to roughly twice India’s 100GW solar mission target. While there is some uncertainty associated with emissions and growth projections, moving to efficient room air conditioning (~30% more efficient than current technology) in parallel with low-GWP refrigerants in room air conditioning could avoid up to ~25 billion tonnes of CO2 in 2030, ~33 billion in 2040, and ~40 billion in 2050, i.e. cumulative savings up to 98 billion tonnes of CO2 by 2050. Therefore, superefficient room ACs using low-GWP refrigerants merit serious consideration to maximize peak load reduction and GHG savings.« less

SIMULATION RESULTS OF SINGLE REFRIGERANTS FOR USE IN A DUAL-CIRCUIT REFRIGERATOR/FREEZER

EPA Science Inventory

The paper reviews the refrigerant/freezer (RF) design and refrigerant selection process that is necessary to design an energy efficient RF that does not use fully halogenated chlorofluorocarbons (CFCs). EPA is interested in phasing out CFCs in RFs to minimize stratospheric ozone ...

77 FR 72763 - Energy Conservation Program: Certification of Commercial and Industrial HVAC, Refrigeration and...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-06

... Commercial and Industrial HVAC, Refrigeration and Water Heating Equipment AGENCY: Office of Energy Efficiency... extension to the compliance date for the certification provisions of commercial refrigeration equipment... refrigeration equipment; commercial HVAC equipment; commercial WH equipment; and walk-in coolers and freezers...

76 FR 57612 - Energy Efficiency Program for Consumer Products: Test Procedures for Residential Refrigerators...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-15

... (collectively, ``refrigeration products''). 75 FR 78810. The amended test procedures for residential... Rule also included amendments to these procedures that will, once finalized, apply to refrigeration... period deadline to ``30 days after the [refrigeration products] standards final rule is made available to...

Frozen Smoke

NASA Technical Reports Server (NTRS)

1998-01-01

Under a NASA SBIR (Small Business Innovative Research) contract with Johnson Space Center, Aspen Systems developed aerogel-based superinsulation. This super-insulation is an innovative, flexible cryogenic insulation with extremely low thermal conductivity. Potential commercial uses include cryogenic applications in the transportation, storage and transfer of cryogens; near room-temperature applications such as refrigerator insulation; and elevated temperature applications such as insulations for high- temperature industrial processes and furnaces.

Low Global Warming Potential Refrigerants for Commercial Refrigeration Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fricke, Brian A.; Sharma, Vishaldeep; Abdelaziz, Omar

Supermarket refrigeration systems account for approximately 50% of supermarket energy use, placing this class of equipment among the highest energy consumers in the commercial building domain. In addition, the commonly used refrigeration system in supermarket applications is the multiplex direct expansion (DX) system, which is prone to refrigerant leaks due to its long lengths of refrigerant piping. This leakage reduces the efficiency of the system and increases the impact of the system on the environment. The high Global Warming Potential (GWP) of the hydrofluorocarbon (HFC) refrigerants commonly used in these systems, coupled with the large refrigerant charge and the highmore » refrigerant leakage rates leads to significant direct emissions of greenhouse gases into the atmosphere. Environmental concerns are driving regulations for the heating, ventilating, air-conditioning and refrigeration (HVAC&R) industry towards lower GWP alternatives to HFC refrigerants. Existing lower GWP refrigerant alternatives include hydrocarbons, such as propane (R-290) and isobutane (R-600a), as well as carbon dioxide (R-744), ammonia (R-717), and R-32. In addition, new lower GWP refrigerant alternatives are currently being developed by refrigerant manufacturers, including hydrofluoro-olefin (HFO) and unsaturated hydrochlorofluorocarbon (HCFO) refrigerants. The selection of an appropriate refrigerant for a given refrigeration application should be based on several factors, including the GWP of the refrigerant, the energy consumption of the refrigeration system over its operating lifetime, and leakage of refrigerant over the system lifetime. For example, focusing on energy efficiency alone may overlook the significant environmental impact of refrigerant leakage; while focusing on GWP alone might result in lower efficiency systems that result in higher indirect impact over the equipment lifetime. Thus, the objective of this Collaborative Research and Development Agreement (CRADA) between Honeywell and the Oak Ridge National Laboratory (ORNL) is to develop a Life Cycle Climate Performance (LCCP) modeling tool for optimally designing HVAC&R equipment with lower life cycle greenhouse gas emissions, and the selection of alternative working fluids that reduce the greenhouse gas emissions of HVAC&R equipment. In addition, an experimental evaluation program is used to measure the coefficient of performance (COP) and refrigerating capacity of various refrigerant candidates, which have differing GWP values, in commercial refrigeration equipment. Through a cooperative effort between industry and government, alternative working fluids will be chosen based on maximum reduction in greenhouse gases at minimal cost impact to the consumer. This project will ultimately result in advancing the goals of reducing greenhouse gas emissions through the use of low GWP working fluids and technologies for HVAC&R and appliance equipment, resulting in cost-competitive products and systems.« less

75 FR 71596 - Energy Efficiency Program for Certain Commercial and Industrial Equipment: Test Procedures for...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-24

... Efficiency Program for Certain Commercial and Industrial Equipment: Test Procedures for Commercial Refrigeration Equipment AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy. ACTION... amendments to its test procedure for commercial refrigeration equipment (CRE). The amendments would update...

Opportunities for Energy Efficiency and Automated Demand Response in Industrial Refrigerated Warehouses in California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lekov, Alex; Thompson, Lisa; McKane, Aimee

2009-05-11

This report summarizes the Lawrence Berkeley National Laboratory's research to date in characterizing energy efficiency and open automated demand response opportunities for industrial refrigerated warehouses in California. The report describes refrigerated warehouses characteristics, energy use and demand, and control systems. It also discusses energy efficiency and open automated demand response opportunities and provides analysis results from three demand response studies. In addition, several energy efficiency, load management, and demand response case studies are provided for refrigerated warehouses. This study shows that refrigerated warehouses can be excellent candidates for open automated demand response and that facilities which have implemented energy efficiencymore » measures and have centralized control systems are well-suited to shift or shed electrical loads in response to financial incentives, utility bill savings, and/or opportunities to enhance reliability of service. Control technologies installed for energy efficiency and load management purposes can often be adapted for open automated demand response (OpenADR) at little additional cost. These improved controls may prepare facilities to be more receptive to OpenADR due to both increased confidence in the opportunities for controlling energy cost/use and access to the real-time data.« less

Influence of the nozzle angle on refrigeration performance of a gas wave refrigerator

NASA Astrophysics Data System (ADS)

Liu, P.; Zhu, Y.; Wang, H.; Zhu, C.; Zou, J.; Wu, J.; Hu, D.

2017-05-01

A gas wave refrigerator (GWR) is a novel refrigerating device that refrigerates a medium by shock waves and expansion waves generated by gas pressure energy. In a typical GWR, the injection energy losses between the nozzle and the expansion tube are essential factors which influence the refrigeration efficiency. In this study, numerical simulations are used to analyze the underlying mechanism of the injection energy losses. The results of simulations show that the vortex loss, mixing energy loss, and oblique shock wave reflection loss are the main factors contributing to the injection energy losses in the expansion tube. Furthermore, the jet angle of the gas is found to dominate the injection energy losses. Therefore, the optimum jet angle is theoretically calculated based on the velocity triangle method. The value of the optimum jet angle is found to be 4^{circ }, 8^{circ }, and 12^{circ } when the refrigeration efficiency is the first-order, second-order, and third-order maximum value over all working ranges of jet frequency, respectively. Finally, a series of experiments are conducted with the jet angle ranging from -4^{circ } to 12^{circ } at a constant expansion ratio. The results indicate the optimal jet angle obtained by the experiments is in good agreement with the calculated value. The isentropic refrigeration efficiency increased by about 4 % after the jet angle was optimized.

Multispectral image enhancement processing for microsat-borne imager

NASA Astrophysics Data System (ADS)

Sun, Jianying; Tan, Zheng; Lv, Qunbo; Pei, Linlin

2017-10-01

With the rapid development of remote sensing imaging technology, the micro satellite, one kind of tiny spacecraft, appears during the past few years. A good many studies contribute to dwarfing satellites for imaging purpose. Generally speaking, micro satellites weigh less than 100 kilograms, even less than 50 kilograms, which are slightly larger or smaller than the common miniature refrigerators. However, the optical system design is hard to be perfect due to the satellite room and weight limitation. In most cases, the unprocessed data captured by the imager on the microsatellite cannot meet the application need. Spatial resolution is the key problem. As for remote sensing applications, the higher spatial resolution of images we gain, the wider fields we can apply them. Consequently, how to utilize super resolution (SR) and image fusion to enhance the quality of imagery deserves studying. Our team, the Key Laboratory of Computational Optical Imaging Technology, Academy Opto-Electronics, is devoted to designing high-performance microsat-borne imagers and high-efficiency image processing algorithms. This paper addresses a multispectral image enhancement framework for space-borne imagery, jointing the pan-sharpening and super resolution techniques to deal with the spatial resolution shortcoming of microsatellites. We test the remote sensing images acquired by CX6-02 satellite and give the SR performance. The experiments illustrate the proposed approach provides high-quality images.

Optimization analysis of the motor cooling method in semi-closed single screw refrigeration compressor

NASA Astrophysics Data System (ADS)

Wang, Z. L.; Shen, Y. F.; Wang, Z. B.; Wang, J.

2017-08-01

Semi-closed single screw refrigeration compressors (SSRC) are widely used in refrigeration and air conditioning systems owing to the advantages of simple structure, balanced forces on the rotor, high volumetric efficiency and so on. In semi-closed SSRCs, motor is often cooled by suction gas or injected refrigerant liquid. Motor cooling method will changes the suction gas temperature, this to a certain extent, is an important factor influencing the thermal dynamic performance of a compressor. Thus the effects of motor cooling method on the performance of the compressor must be studied. In this paper mathematical models of motor cooling process by using these two methods were established. Influences of motor cooling parameters such as suction gas temperature, suction gas quantity, temperature of the injected refrigerant liquid and quantity of the injected refrigerant liquid on the thermal dynamic performance of the compressor were analyzed. The performances of the compressor using these two kinds of motor cooling methods were compared. The motor cooling capacity of the injected refrigerant liquid is proved to be better than the suction gas. All analysis results obtained can be useful for optimum design of the motor cooling process to improve the efficiency and the energy efficiency of the compressor.

Supermarket refrigeration assessment for the Commonwealth Electric Company

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsaros, T.L.; Walker, D.H.

The Commonwealth Electric Company (COM/Electric) has initiated an incentive program to promote electric energy conservation within its service territory. The Electric Power Research Institute (EPRI) has assisted COM/Electric in assessing the impact on the utility and its customers of implementing energy efficient supermarket refrigeration in retrofit applications. The primary task of this assessment was to contact the supermarket chains and refrigeration contractors and suppliers in the COM/Electric service territory to determine the type of refrigeration employed and standard or novel retrofit equipment implemented in supermarkets. With this information, estimates were made of the potential energy savings that COM/Electric and themore » supermarkets could realize if supermarkets were retrofitted with energy efficient refrigeration equipment. It was determined that the refrigerated display case features offering the greatest potential for savings through retrofit installations include doors for medium temperature multideck cases, high-efficiency fan motors, anti-sweat heater controls, and vinyl strip curtains for walk-in coolers. The retrofit components associated with the compressor machine room that offer the greatest potential for savings include the use of low heat pressure control, hot gas defrost, and external liquid-suction heat exchangers and remote evaporative subcoolers for low temperature refrigeration. 6 refs., 14 figs., 26 tabs.« less

Avoided electricity subsidy payments can finance substantial appliance efficiency incentive programs: Case study of Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leventis, Greg; Gopal, Anand; Rue du Can, Stephane de la

Numerous countries use taxpayer funds to subsidize residential electricity for a variety of socioeconomic objectives. These subsidies lower the value of energy efficiency to the consumer while raising it for the government. Further, while it would be especially helpful to have stringent Minimum Energy Performance Standards (MEPS) for appliances and buildings in this environment, they are hard to strengthen without imposing a cost on ratepayers. In this secondbest world, where the presence of subsidies limits the government’s ability to strengthen standards, we find that avoided subsidies are a readily available source of financing for energy efficiency incentive programs. Here, wemore » introduce the LBNL Energy Efficiency Revenue Analysis (LEERA) model to estimate the appliance efficiency improvements that can be achieved in Mexico by the revenue neutral financing of incentive programs from avoided subsidy payments. LEERA uses the detailed techno-economic analysis developed by LBNL for the Super-efficient Equipment and Appliance Deployment (SEAD) Initiative to calculate the incremental costs of appliance efficiency improvements. We analyze Mexico’s tariff structures and the long-run marginal cost of supply to calculate the marginal savings for the government from appliance efficiency. We find that avoided subsidy payments alone can finance incentive programs that cover the full incremental cost of refrigerators that are 27% more efficient and TVs that are 32% more efficient than baseline models. We find less substantial market transformation potential for room ACs primarily because AC energy savings occur at less subsidized tariffs.« less

Experimental evaluation of refrigerant mass charge and ambient air temperature effects on performance of air-conditioning systems

NASA Astrophysics Data System (ADS)

Deymi-Dashtebayaz, Mahdi; Farahnak, Mehdi; Moraffa, Mojtaba; Ghalami, Arash; Mohammadi, Nima

2018-03-01

In this paper the effects of refrigerant charge amount and ambient air temperature on performance and thermodynamic condition of refrigerating cycle in the split type air-conditioner have been investigated. Optimum mass charge is the point at which the energy efficiency ratio (EER) of refrigeration cycle becomes the maximum. Experiments have been conducted over a range of refrigerant mass charge from 540 to 840 g and a range of ambient temperature from 27 to 45 °C, in a 12,000 Btu/h split air-conditioner as case study. The various parameters have been considered to evaluate the cooling rate, energy efficiency ratio (EER), mass charge effect and thermodynamic cycle of refrigeration system with R22 refrigerant gas. Results confirmed that the lack of appropriate refrigerant mass charge causes the refrigeration system not to reach its maximum cooling capacity. The highest cooling capacity achieved was 3.2 kW (11,000 Btu/h). The optimum mass charge and corresponding EER of studied system have been obtained about 640 g and 2.5, respectively. Also, it is observed that EER decreases by 30% as ambient temperature increases from 27 °C to 45 °C. By optimization of the refrigerant mass charge in refrigerating systems, about 785 GWh per year of electric energy can be saved in Iran's residential sector.

Alternative refrigerants and refrigeration cycles for domestic refrigerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sand, J.R.; Rice, C.L.; Vineyard, E.A.

1992-12-01

This project initially focused on using nonazeotropic refrigerant mixtures (NARMs) in a two-evaporator refrigerator-freezer design using two stages of liquid refrigerant subcooling. This concept was proposed and tested in 1975. The work suggested that the concept was 20% more efficient than the conventional one-evaporator refrigerator-freezer (RF) design. After considerable planning and system modeling based on using a NARM in a Lorenz-Meutzner (L-M) RF, the program scope was broadened to include investigation of a ``dual-loop`` concept where energy savings result from exploiting the less stringent operating conditions needed to satisfy cooling, of the fresh food section. A steady-state computer model (CYCLE-Z)more » capable of simulating conventional, dual loop, and L-M refrigeration cycles was developed. This model was used to rank the performance of 20 ozone-safe NARMs in the L-M refrigeration cycle while key system parameters were systematically varied. The results indicated that the steady-state efficiency of the L-M design was up to 25% greater than that of a conventional cycle. This model was also used to calculate the performance of other pure refrigerants relative to that of dichlorodifluoromethane, R-12, in conventional and dual-loop RF designs. Projected efficiency gains for these cycles were more modest, ranging from 0 to 10%. Individual compressor calorimeter tests of nine combinations of evaporator and condenser temperatures usually used to map RF compressor performance were carried out with R-12 and two candidate L-M NARMs in several compressors. Several models of a commercially produced two-evaporator RF were obtained as test units. Two dual-loop RF designs were built and tested as part of this project.« less

R&D of high reliable refrigeration system for superconducting generators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hosoya, T.; Shindo, S.; Yaguchi, H.

1996-12-31

Super-GM carries out R&D of 70 MW class superconducting generators (model machines), refrigeration system and superconducting wires to apply superconducting technology to electric power apparatuses. The helium refrigeration system for keeping field windings of superconducting generator (SCG) in cryogenic environment must meet the requirement of high reliability for uninterrupted long term operation of the SCG. In FY 1992, a high reliable conventional refrigeration system for the model machines was integrated by combining components such as compressor unit, higher temperature cold box and lower temperature cold box which were manufactured utilizing various fundamental technologies developed in early stage of the projectmore » since 1988. Since FY 1993, its performance tests have been carried out. It has been confirmed that its performance was fulfilled the development target of liquefaction capacity of 100 L/h and impurity removal in the helium gas to < 0.1 ppm. Furthermore, its operation method and performance were clarified to all different modes as how to control liquefaction rate and how to supply liquid helium from a dewar to the model machine. In addition, the authors have made performance tests and system performance analysis of oil free screw type and turbo type compressors which greatly improve reliability of conventional refrigeration systems. The operation performance and operational control method of the compressors has been clarified through the tests and analysis.« less

Development of Low Global Warming Potential Refrigerant Solutions for Commercial Refrigeration Systems using a Life Cycle Climate Performance Design Tool

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelaziz, Omar; Fricke, Brian A; Vineyard, Edward Allan

Commercial refrigeration systems are known to be prone to high leak rates and to consume large amounts of electricity. As such, direct emissions related to refrigerant leakage and indirect emissions resulting from primary energy consumption contribute greatly to their Life Cycle Climate Performance (LCCP). In this paper, an LCCP design tool is used to evaluate the performance of a typical commercial refrigeration system with alternative refrigerants and minor system modifications to provide lower Global Warming Potential (GWP) refrigerant solutions with improved LCCP compared to baseline systems. The LCCP design tool accounts for system performance, ambient temperature, and system load; systemmore » performance is evaluated using a validated vapor compression system simulation tool while ambient temperature and system load are devised from a widely used building energy modeling tool (EnergyPlus). The LCCP design tool also accounts for the change in hourly electricity emission rate to yield an accurate prediction of indirect emissions. The analysis shows that conventional commercial refrigeration system life cycle emissions are largely due to direct emissions associated with refrigerant leaks and that system efficiency plays a smaller role in the LCCP. However, as a transition occurs to low GWP refrigerants, the indirect emissions become more relevant. Low GWP refrigerants may not be suitable for drop-in replacements in conventional commercial refrigeration systems; however some mixtures may be introduced as transitional drop-in replacements. These transitional refrigerants have a significantly lower GWP than baseline refrigerants and as such, improved LCCP. The paper concludes with a brief discussion on the tradeoffs between refrigerant GWP, efficiency and capacity.« less

Refrigeration system having standing wave compressor

DOEpatents

Lucas, Timothy S.

1992-01-01

A compression-evaporation refrigeration system, wherein gaseous compression of the refrigerant is provided by a standing wave compressor. The standing wave compressor is modified so as to provide a separate subcooling system for the refrigerant, so that efficiency losses due to flashing are reduced. Subcooling occurs when heat exchange is provided between the refrigerant and a heat pumping surface, which is exposed to the standing acoustic wave within the standing wave compressor. A variable capacity and variable discharge pressure for the standing wave compressor is provided. A control circuit simultaneously varies the capacity and discharge pressure in response to changing operating conditions, thereby maintaining the minimum discharge pressure needed for condensation to occur at any time. Thus, the power consumption of the standing wave compressor is reduced and system efficiency is improved.

Energy Efficient Commercial Refrigeration with Carbon Dioxide Refrigerant and Scroll Expanders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dieckmann, John

Current supermarket refrigeration systems are built around conventional fluorocarbon refrigerants – HFC-134a and the HFC blends R-507 and R404A, which replaced the CFC refrigerants, R-12 and R-502, respectively, used prior to the Montreal Protocol phase out of ozone depleting substances. While the HFC refrigerants are non-ozone depleting, they are strong greenhouse gases, so there has been continued interest in replacing them, particularly in applications with above average refrigerant leakage. Large supermarket refrigeration systems have proven to be particularly difficult to maintain in a leak-tight condition. Refrigerant charge losses of 15% of total charge per year are the norm, making themore » global warming impact of refrigerant emissions comparable to that associated with the energy consumption of these systems.« less

Performance of R-410A Alternative Refrigerants in a Reciprocating Compressor Designed for Air Conditioning Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shrestha, Som S; Vineyard, Edward Allan; Mumpower, Kevin

In response to environmental concerns raised by the use of refrigerants with high Global Warming Potential (GWP), the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) has launched an industry-wide cooperative research program, referred to as the Low-GWP Alternative Refrigerants Evaluation Program (AREP), to identify and evaluate promising alternative refrigerants for major product categories. After successfully completing the first phase of the program in December 2013, AHRI launched a second phase of the Low-GWP AREP in 2014 to continue research in areas that were not previously addressed, including refrigerants in high ambient conditions, refrigerants in applications not tested in the first phase,more » and new refrigerants identified since testing for the program began. Although the Ozone Depletion Potential of R-410A is zero, this refrigerant is under scrutiny due to its high GWP. Several candidate alternative refrigerants have already demonstrated low global warming potential. Performance of these low-GWP alternative refrigerants is being evaluated for Air conditioning and heat pump applications to ensure acceptable system capacity and efficiency. This paper reports the results of a series of compressor calorimeter tests conducted for the second phase of the AREP to evaluate the performance of R-410A alternative refrigerants in a reciprocating compressor designed for air conditioning systems. It compares performance of alternative refrigerants ARM-71A, L41-1, DR-5A, D2Y-60, and R-32 to that of R-410A over a wide range of operating conditions. The tests showed that, in general, cooling capacities were slightly lower (except for the R-32), but energy efficiency ratios (EER) of the alternative refrigerants were comparable to that of R-410A.« less

77 FR 1474 - Decision and Order Granting a Waiver to Samsung From the Department of Energy Residential...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-10

... DEPARTMENT OF ENERGY Office of Energy Efficiency and Renewable Energy [Case No. RF-018; Case No... Refrigerator and Refrigerator-Freezer Test Procedures AGENCY: Office of Energy Efficiency and Renewable Energy... characteristics. 10 CFR 430.27(b)(1)(iii). The Assistant Secretary for Energy Efficiency and Renewable Energy (the...

Stirling Air Conditioner for Compact Cooling

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-09-01

BEETIT Project: Infinia is developing a compact air conditioner that uses an unconventional high efficient Stirling cycle system (vs. conventional vapor compression systems) to produce cool air that is energy efficient and does not rely on polluting refrigerants. The Stirling cycle system is a type of air conditioning system that uses a motor with a piston to remove heat to the outside atmosphere using a gas refrigerant. To date, Stirling systems have been expensive and have not had the right kind of heat exchanger to help cool air efficiently. Infinia is using chip cooling technology from the computer industry tomore » make improvements to the heat exchanger and improve system performance. Infinia’s air conditioner uses helium gas as refrigerant, an environmentally benign gas that does not react with other chemicals and does not burn. Infinia’s improvements to the Stirling cycle system will enable the cost-effective mass production of high-efficiency air conditioners that use no polluting refrigerants.« less

Thermoelectric refrigerator

NASA Technical Reports Server (NTRS)

Park, Brian V. (Inventor); Smith, Jr., Malcolm C. (Inventor); McGrath, Ralph D. (Inventor); Gilley, Michael D. (Inventor); Criscuolo, Lance (Inventor); Nelson, John L. (Inventor)

1996-01-01

A refrigerator is provided which combines the benefits of superinsulation materials with thermoelectric devices and phase change materials to provide an environmentally benign system that is energy efficient and can maintain relatively uniform temperatures for extended periods of time with relatively low electrical power requirements. The refrigerator includes a thermoelectric assembly having a thermoelectric device with a hot sink and a cold sink. The superinsulation materials include a plurality of vacuum panels. The refrigerator is formed from an enclosed structure having a door. The vacuum panels may be contained within the walls of the enclosed structure and the door. By mounting the thermoelectric assembly on the door, the manufacturer of the enclosed structure is simplified and the overall R rating of the refrigerator increased. Also an electrical motor and propellers may be mounted on the door to assist in the circulation of air to improve the efficiency of the cold sink and the hot sink. A propeller and/or impeller is preferably mounted within the refrigerator to assist in establishing the desired air circulation flow path.

Development of Carbon Dioxide Hermitic Compressor

NASA Astrophysics Data System (ADS)

Imai, Satoshi; Oda, Atsushi; Ebara, Toshiyuki

Because of global environmental problems, the existing refrigerants are to be replaced with natural refrigerants. CO2 is one of the natural refrigerants and environmentally safe, inflammable and non-toxic refrigerant. Therefore high efficiency compressor that can operate with natural refrigerants, especially CO2, needs to be developed. We developed a prototype CO2 hermetic compressor, which is able to use in carbon dioxide refrigerating systems for practical use. The compressor has two rolling pistons, and it leads to low vibrations, low noise. In additions, two-stage compression with two cylinders is adopted, because pressure difference is too large to compress in one stage. And inner pressure of the shell case is intermediate pressure to minimize gas leakage between compressing rooms and inner space of shell case. Intermediate pressure design enabled to make the compressor smaller in size and lighter in weight. As a result, the compressor achieved high efficiency and high reliability by these technology. We plan to study heat pump water heater, cup vending machine and various applications with CO2 compressor.

An experimental study for a miniature Stirling refrigerator

NASA Technical Reports Server (NTRS)

Li, S.; Chen, G.; Huang, Z.; Zhang, F.; Cui, C.; Li, J.

1985-01-01

Experimental results of a miniature two-stage Stirling cryocooler are introduced. The influence of filling gas pressure and refrigeration temperature on the refrigerating capacity along with the relationship between parameters was measured. The valley pressure corresponding to the lowest refrigeration temperature and the cooldown time versus operating pressure are discussed. The coefficient of performance and thermodynamic efficiency of the cryocooler are calculated based on experimental data.

75 FR 24824 - Energy Efficiency Program for Consumer Products: Public Meeting and Availability of the Framework...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-06

... Availability of the Framework Document for Commercial Refrigeration Equipment AGENCY: Office of Energy... data collection process to consider amended energy conservation standards for commercial refrigeration... Energy, Building Technologies Program, Mailstop EE-2J, Framework Document for Commercial Refrigeration...

Combined Brayton-JT cycles with refrigerants for natural gas liquefaction

NASA Astrophysics Data System (ADS)

Chang, Ho-Myung; Park, Jae Hoon; Lee, Sanggyu; Choe, Kun Hyung

2012-06-01

Thermodynamic cycles for natural gas liquefaction with single-component refrigerants are investigated under a governmental project in Korea, aiming at new processes to meet the requirements on high efficiency, large capacity, and simple equipment. Based upon the optimization theory recently published by the present authors, it is proposed to replace the methane-JT cycle in conventional cascade process with a nitrogen-Brayton cycle. A variety of systems to combine nitrogen-Brayton, ethane-JT and propane-JT cycles are simulated with Aspen HYSYS and quantitatively compared in terms of thermodynamic efficiency, flow rate of refrigerants, and estimated size of heat exchangers. A specific Brayton-JT cycle is suggested with detailed thermodynamic data for further process development. The suggested cycle is expected to be more efficient and simpler than the existing cascade process, while still taking advantage of easy and robust operation with single-component refrigerants.

Liquid over-feeding refrigeration system and method with integrated accumulator-expander-heat exchanger

DOEpatents

Mei, Viung C.; Chen, Fang C.

1997-01-01

A refrigeration system having a vapor compression cycle utilizing a liquid over-feeding operation with an integrated accumulator-expander-heat exchanger. Hot, high-pressure liquid refrigerant from the condenser passes through one or more lengths of capillary tubing substantially immersed in a pool liquid refrigerant in the accumulator-expander-heat exchanger for simultaneously sub-cooling and expanding the liquid refrigerant while vaporizing liquid refrigerant from the pool for the return thereof to the compressor as saturated vapor. The sub-cooling of the expanded liquid provides for the flow of liquid refrigerant into the evaporator for liquid over-feeding the evaporator and thereby increasing the efficiency of the evaporation cycle.

Liquid over-feeding refrigeration system and method with integrated accumulator-expander-heat exchanger

DOEpatents

Mei, V.C.; Chen, F.C.

1997-04-22

A refrigeration system is described having a vapor compression cycle utilizing a liquid over-feeding operation with an integrated accumulator-expander-heat exchanger. Hot, high-pressure liquid refrigerant from the condenser passes through one or more lengths of capillary tubing substantially immersed in a pool liquid refrigerant in the accumulator-expander-heat exchanger for simultaneously sub-cooling and expanding the liquid refrigerant while vaporizing liquid refrigerant from the pool for the return thereof to the compressor as saturated vapor. The sub-cooling of the expanded liquid provides for the flow of liquid refrigerant into the evaporator for liquid over-feeding the evaporator and thereby increasing the efficiency of the evaporation cycle. 4 figs.

Manganese Nitride Sorption Joule-Thomson Refrigerator

NASA Technical Reports Server (NTRS)

Jones, Jack A.; Phillips, Wayne M.

1992-01-01

Proposed sorption refrigeration system of increased power efficiency combines MnxNy sorption refrigeration stage with systems described in "Regenerative Sorption Refrigerator" (NPO-17630). Measured pressure-vs-composition isotherms for reversible chemisorption of N2 in MnxNy suggest feasibility to incorporate MnxNy chemisorption stage in Joule-Thomson cryogenic system. Discovery represents first known reversible nitrogen chemisorption compression system. Has potential in nitrogen-isotope separation, nitrogen purification, or contamination-free nitrogen compression.

A review of pulse tube refrigeration

NASA Technical Reports Server (NTRS)

Radebaugh, Ray

1990-01-01

This paper reviews the development of the three types of pulse tube refrigerators: basic, resonant, and orifice types. The principles of operation are given. It is shown that the pulse tube refrigerator is a variation of the Stirling-cycle refrigerator, where the moving displacer is substituted by a heat transfer mechanism or by an orifice to bring about the proper phase shifts between pressure and mass flow rate. A harmonic analysis with phasors is described which gives reasonable results for the refrigeration power, yet is simple enough to make clear the processes which give rise to the refrigeration. The efficiency and refrigeration power are compared with those of other refrigeration cycles. A brief review is given of the research being done at various laboratories on both one- and two-stage pulse tubes. A preliminary assessment of the role of pulse tube refrigerators is discussed.

78 FR 37495 - Appliance Standards and Rulemaking Federal Advisory Committee: Notice of Open Meetings for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-21

... Rulemaking Federal Advisory Committee: Notice of Open Meetings for the Commercial HVAC, WH, and Refrigeration... Requirements for Commercial HVAC, WH, and Refrigeration Equipment AGENCY: Office of Energy Efficiency and... Heating (WH), and Refrigeration Certification Working Group (Commercial Certification Group). The purpose...

78 FR 22431 - Appliance Standards and Rulemaking Federal Advisory Committee: Notice of Open Meeting for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-16

... for the Commercial HVAC, WH, and Refrigeration Certification Working Group and Announcement of Working... Refrigeration Equipment AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy. ACTION..., Ventilation, and Air-conditioning (HVAC), Water Heating (WH), and Refrigeration Certification Working Group...

78 FR 49699 - Appliance Standards and Rulemaking Federal Advisory Committee: Notice of Open Meetings for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-15

... Meetings for the Commercial HVAC, WH, and Refrigeration Certification Working Group and Announcement of... Refrigeration Equipment AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy. ACTION..., Ventilation, and Air-conditioning (HVAC), Water Heating (WH), and Refrigeration Certification Working Group...

Two-statge sorption type cryogenic refrigerator including heat regeneration system

NASA Technical Reports Server (NTRS)

Jones, Jack A. (Inventor); Wen, Liang-Chi (Inventor); Bard, Steven (Inventor)

1989-01-01

A lower stage chemisorption refrigeration system physically and functionally coupled to an upper stage physical adsorption refrigeration system. Waste heat generated by the lower stage cycle is regenerated to fuel the upper stage cycle thereby greatly improving the energy efficiency of a two-stage sorption refrigerator. The two stages are joined by disposing a first pressurization chamber providing a high pressure flow of a first refrigerant for the lower stage refrigeration cycle within a second pressurization chamber providing a high pressure flow of a second refrigerant for the upper stage refrigeration cycle. The first pressurization chamber is separated from the second pressurization chamber by a gas-gap thermal switch which at times is filled with a thermoconductive fluid to allow conduction of heat from the first pressurization chamber to the second pressurization chamber.

The cryogenics design of the SuperCDMS SNOLAB experiment

NASA Astrophysics Data System (ADS)

Hollister, M. I.; Bauer, D. A.; Dhuley, R. C.; Lukens, P.; Martin, L. D.; Ruschman, M. K.; Schmitt, R. L.; Tatkowski, G. L.

2017-12-01

The Super Cryogenic Dark Matter Search (SuperCDMS) experiment is a direct detection dark matter experiment intended for deployment to the SNOLAB underground facility in Ontario, Canada. With a payload of up to 186 germanium and silicon crystal detectors operating below 15 mK, the cryogenic architecture of the experiment is complex. Further, the requirement that the cryostat presents a low radioactive background to the detectors limits the materials and techniques available for construction, and heavily influences the design of the cryogenics system. The resulting thermal architecture is a closed cycle (no liquid cryogen) system, with stages at 50 and 4 K cooled with gas and fluid circulation systems and stages at 1 K, 250 mK and 15 mK cooled by the lower temperature stages of a large, cryogen-free dilution refrigerator. This paper describes the thermal design of the experiment, including details of the cooling systems, mechanical designs and expected performance of the system under operational conditions.

Gas-fired duplex free-piston Stirling refrigerator

NASA Astrophysics Data System (ADS)

Urieli, L.

1984-03-01

The duplex free-piston Stirling refrigerator is a potentially high efficiency, high reliability device which is ideally suited to the home appliance field, in particular as a gas-fired refrigerator. It has significant advantages over other equivalent devices including freedom from halogenated hydrocarbons, extremely low temperatures available at a high efficiency, integrated water heating, and simple burner system control. The design and development of a portable working demonstration gas-fired duplex Stirling refrigeration unit is described. A unique combination of computer aided development and experimental development was used, enabling a continued interaction between the theoretical analysis and practical testing and evaluation. A universal test rig was developed in order to separately test and evaluate major subunits, enabling a smooth system integration phase.

Electron refrigeration in hybrid structures with spin-split superconductors

NASA Astrophysics Data System (ADS)

Rouco, M.; Heikkilä, T. T.; Bergeret, F. S.

2018-01-01

Electron tunneling between superconductors and normal metals has been used for an efficient refrigeration of electrons in the latter. Such cooling is a nonlinear effect and usually requires a large voltage. Here we study the electron cooling in heterostructures based on superconductors with a spin-splitting field coupled to normal metals via spin-filtering barriers. The cooling power shows a linear term in the applied voltage. This improves the coefficient of performance of electron refrigeration in the normal metal by shifting its optimum cooling to lower voltage, and also allows for cooling the spin-split superconductor by reverting the sign of the voltage. We also show how tunnel coupling spin-split superconductors with regular ones allows for a highly efficient refrigeration of the latter.

Total environmental warming impact (TEWI) calculations for alternative automative air-conditioning systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sand, J.R.; Fischer, S.K.

1997-01-01

The Montreal Protocol phase-out of chlorofluorocarbons (CFCs) has required manufacturers to develop refrigeration and air-conditioning systems that use refrigerants that can not damage stratospheric ozone. Most refrigeration industries have adapted their designs to use hydrochlorofluorocarbon (HCFC) or hydrofluorocarbon (HFC) refrigerants; new automobile air- conditioning systems use HFC-134a. These industries are now being affected by scientific investigations of greenhouse warming and questions about the effects of refrigerants on global warming. Automobile air-conditioning has three separate impacts on global warming; (1) the effects of refrigerant inadvertently released to the atmosphere from accidents, servicing, and leakage; (2) the efficiency of the cooling equipmentmore » (due to the emission of C0{sub 2} from burning fuel to power the system); and (3) the emission of C0{sub 2} from burning fuel to transport the system. The Total Equivalent Warming Impact (TEWI) is an index that should be used to compare the global warming effects of alternative air-conditioning systems because it includes these contributions from the refrigerant, cooling efficiency, and weight. This paper compares the TEWI of current air-conditioning systems using HFC-134a with that of transcritical vapor compression system using carbon dioxide and systems using flammable refrigerants with secondary heat transfer loops. Results are found to depend on both climate and projected efficiency of C0{sub 2}systems. Performance data on manufacturing prototype systems are needed to verify the potential reductions in TEWI. Extensive field testing is also required to determine the performance, reliability, and ``serviceability`` of each alternative to HFC-134a to establish whether the potential reduction of TEWI can be achieved in a viable consumer product.« less

Electroluminescent refrigeration by ultra-efficient GaAs light-emitting diodes

NASA Astrophysics Data System (ADS)

Patrick Xiao, T.; Chen, Kaifeng; Santhanam, Parthiban; Fan, Shanhui; Yablonovitch, Eli

2018-05-01

Electroluminescence—the conversion of electrons to photons in a light-emitting diode (LED)—can be used as a mechanism for refrigeration, provided that the LED has an exceptionally high quantum efficiency. We investigate the practical limits of present optoelectronic technology for cooling applications by optimizing a GaAs/GaInP double heterostructure LED. We develop a model of the design based on the physics of detailed balance and the methods of statistical ray optics, and predict an external luminescence efficiency of ηext = 97.7% at 263 K. To enhance the cooling coefficient of performance, we pair the refrigerated LED with a photovoltaic cell, which partially recovers the emitted optical energy as electricity. For applications near room temperature and moderate power densities (1.0-10 mW/cm2), we project that an electroluminescent refrigerator can operate with up to 1.7× the coefficient of performance of thermoelectric coolers with ZT = 1, using the material quality in existing GaAs devices. We also predict superior cooling efficiency for cryogenic applications relative to both thermoelectric and laser cooling. Large improvements to these results are possible with optoelectronic devices that asymptotically approach unity luminescence efficiency.

Dual source heat pump

DOEpatents

Ecker, Amir L.; Pietsch, Joseph A.

1982-01-01

What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating the fluid in heat exchange relationship with a refrigerant fluid; at least two refrigerant heat exchangers, one for effecting heat exchange with the fluid and a second for effecting heat exchange between refrigerant and a heat exchange fluid and the ambient air; a compressor for efficiently compressing the refrigerant; at least one throttling valve for throttling liquid refrigerant; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and direction of flow of the refrigerant therethrough for selecting a particular mode of operation. The heat exchange fluid provides energy for defrosting the second heat exchanger when operating in the air source mode and also provides a alternate source of heat.

78 FR 35898 - Decision and Order Granting a Waiver to Samsung From the Department of Energy Residential...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-14

... Refrigerator-Freezer Test Procedures AGENCY: Office of Energy Efficiency and Renewable Energy, Department of... from the DOE electric refrigerator and refrigerator-freezer test procedures for specific basic models set forth in its petition for waiver. In its petition, Samsung provides an alternate test procedure...

78 FR 35901 - Decision and Order Granting a Waiver to Samsung From the Department of Energy Residential...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-14

... Refrigerator-Freezer Test Procedures AGENCY: Office of Energy Efficiency and Renewable Energy, Department of... from the DOE electric refrigerator and refrigerator-freezer test procedures for specific basic models set forth in its petition for waiver. In its petition, Samsung provides an alternate test procedure...

Efficient electrochemical refrigeration power plant using natural gas with ∼100% CO2 capture

NASA Astrophysics Data System (ADS)

Al-musleh, Easa I.; Mallapragada, Dharik S.; Agrawal, Rakesh

2015-01-01

We propose an efficient Natural Gas (NG) based Solid Oxide Fuel Cell (SOFC) power plant equipped with ∼100% CO2 capture. The power plant uses a unique refrigeration based process to capture and liquefy CO2 from the SOFC exhaust. The capture of CO2 is carried out via condensation and purification using two rectifying columns operating at different pressures. The uncondensed gas mixture, comprising of relatively high purity unconverted fuel, is recycled to the SOFC and found to boost the power generation of the SOFC by 22%, when compared to a stand alone SOFC. If Liquefied Natural Gas (LNG) is available at the plant gate, then the refrigeration available from its evaporation is used for CO2 Capture and Liquefaction (CO2CL). If NG is utilized, then a Mixed Refrigerant (MR) vapor compression cycle is utilized for CO2CL. Alternatively, the necessary refrigeration can be supplied by evaporating the captured liquid CO2 at a lower pressure, which is then compressed to supercritical pressures for pipeline transportation. From rigorous simulations, the power generation efficiency of the proposed processes is found to be 70-76% based on lower heating value (LHV). The benefit of the proposed processes is evident when the efficiency of 73% for a conventional SOFC-Gas turbine power plant without CO2 capture is compared with an equivalent efficiency of 71.2% for the proposed process with CO2CL.

Study of reverse Brayton cryocooler with Helium-Neon mixture for HTS cable

NASA Astrophysics Data System (ADS)

Dhillon, A. K.; Ghosh, P.

2017-12-01

As observed in the earlier studies, helium is more efficient than neon as a refrigerant in a reverse Brayton cryocooler (RBC) from the thermodynamic point of view. However, the lower molecular weight of helium leads to higher refrigerant inventory as compared to neon. Thus, helium is suitable to realize the high thermodynamic efficiency of RBC whereas neon is appropriate for the compactness of the RBC. A binary mixture of helium and neon can be used to achieve high thermodynamic efficiency in the compact reverse Brayton cycle (RBC) based cryocooler. In this paper, an attempt has been made to analyze the thermodynamic performance of the RBC with a binary mixture of helium and neon as the working fluid to provide 1 kW cooling load for high temperature superconductor (HTS) power cables working with a temperature range of 50 K to 70 K. The basic RBC is simulated using Aspen HYSYS V8.6®, a commercial process simulator. Sizing of each component based on the optimized process parameters for each refrigerant is performed based on a computer code developed using Engineering Equation Solver (EES-V9.1). The recommendation is provided for the optimum mixture composition of the refrigerant based on the trade-off factors like thermodynamic efficiency such as the exergy efficiency and equipment considerations. The outcome of this study may be useful for recommending a suitable refrigerant for the RBC operating at a temperature level of 50 K to 70 K.

Two stage sorption type cryogenic refrigerator including heat regeneration system

NASA Technical Reports Server (NTRS)

Jones, Jack A. (Inventor); Wen, Liang-Chi (Inventor); Bard, Steven (Inventor)

1989-01-01

A lower stage chemisorption refrigeration system physically and functionally coupled to an upper stage physical adsorption refrigeration system is disclosed. Waste heat generated by the lower stage cycle is regenerated to fuel the upper stage cycle thereby greatly improving the energy efficiency of a two-stage sorption refrigerator. The two stages are joined by disposing a first pressurization chamber providing a high pressure flow of a first refrigerant for the lower stage refrigeration cycle within a second pressurization chamber providing a high pressure flow of a second refrigerant for the upper stage refrigeration cycle. The first pressurization chamber is separated from the second pressurization chamber by a gas-gap thermal switch which at times is filled with a thermoconductive fluid to allow conduction of heat from the first pressurization chamber to the second pressurization chamber.

Evaluation of railway transportation efficiency based on super-cross efficiency

NASA Astrophysics Data System (ADS)

Kuang, Xiuyuan

2018-01-01

The efficiency of railway transportation is an important index. It can measure the development of railway transportation enterprises, and the efficiency of railway transportation has become a hot issue in the study of railway development. Data envelopment analysis (DEA) has been widely applied to railway efficiency analysis. In this paper, BBC model and super-cross efficiency model are constructed by using DEA theory, taking the 18 Railway Bureau as the research object, with the mileage, the number of employees, locomotive number, average daily loading number as input indicators, the passenger turnover, freight turnover and transport income as output indicators, then calculated and evaluated comprehensive efficiency, pure technical efficiency and scale efficiency. We get that the super-cross efficiency is more in line with the actual situation. Getting the super-cross efficiency is more in line with the actual situation.

Design of solar adsorption refrigeration system with CPC and study on the heat and mass transfer performance

NASA Astrophysics Data System (ADS)

Du, W. P.; Li, M.; Wang, Y. F.; He, J. H.; He, J. X.

2017-11-01

To overcome the problem that the heat source temperature is limited and the lower part of the adsorption tube cannot effectively absorb the solar radiation when solar radiation as the heat source of the adsorption refrigeration system. From the perspective of enhancing the adsorption refrigeration unit tube to absorb solar radiation, thereby strengthening the heat transfer characteristic of adsorption bed, which can improve the efficiency of the refrigeration unit refrigerating capacity and system refrigeration efficiency. Solar adsorption refrigeration system based on CPC was designed and constructed in this paper. The heat and mass transfer performance of the adsorption refrigeration system were studied. The experimental results show that the temperature of the adsorption bed with parabolic concentrating structure can rise to 100°C under low irradiation condition. When the irradiation intensity is 600 w/m2 and 400 w/m2, the average temperature rising to desorption temperature reaches 0.67°C and 0.50°C, respectively. It can effectively solve the problem that the conventional adsorption bed is difficult to reach the required desorption temperature due to the low power density of the sunlight. In the experiment, the system COP were 0.166 and 0.143 when the system in the irradiance of 600 w/m2 and 400 w/m2.

Investigation of waste heat recovery of binary geothermal plants using single component refrigerants

NASA Astrophysics Data System (ADS)

Unverdi, M.

2017-08-01

In this study, the availability of waste heat in a power generating capacity of 47.4 MW in Germencik Geothermal Power Plant has been investigated via binary geothermal power plant. Refrigerant fluids of 7 different single components such as R-134a, R-152a, R-227ea, R-236fa, R-600, R-143m and R-161 have been selected. The binary cycle has been modeled using the waste heat equaling to mass flow rate of 100 kg/s geothermal fluid. While the inlet temperature of the geothermal fluid into the counter flow heat exchanger has been accepted as 110°C, the outlet temperature has been accepted as 70°C. The inlet conditions have been determined for the refrigerants to be used in the binary cycle. Finally, the mass flow rate of refrigerant fluid and of cooling water and pump power consumption and power generated in the turbine have been calculated for each inlet condition of the refrigerant. Additionally, in the binary cycle, energy and exergy efficiencies have been calculated for 7 refrigerants in the availability of waste heat. In the binary geothermal cycle, it has been found out that the highest exergy destruction for all refrigerants occurs in the heat exchanger. And the highest and lowest first and second law efficiencies has been obtained for R-600 and R-161 refrigerants, respectively.

Counterflow absorber for an absorption refrigeration system

DOEpatents

Reimann, Robert C.

1984-01-01

An air-cooled, vertical tube absorber for an absorption refrigeration system is disclosed. Strong absorbent solution is supplied to the top of the absorber and refrigerant vapor is supplied to the bottom of the absorber to create a direct counterflow of refrigerant vapor and absorbent solution in the absorber. The refrigeration system is designed so that the volume flow rate of refrigerant vapor in the tubes of the absorber is sufficient to create a substantially direct counterflow along the entire length of each tube in the absorber. This provides several advantages for the absorber such as higher efficiency and improved heat transfer characteristics, and allows improved purging of non-condensibles from the absorber.

More effective wet turboexpander for the nuclotron helium refrigerators

NASA Astrophysics Data System (ADS)

Agapov, N. N.; Batin, V. I.; Davydov, A. B.; Khodzhibagian, H. G.; Kovalenko, A. D.; Perestoronin, G. A.; Sergeev, I. I.; Stulov, V. L.; Udut, V. N.

2002-05-01

In order to raise the efficiency of cryogenic refrigerators and liquefiers, it is very important to replace the JT process, which involves large losses of exergy, by the improved process of adiabatic expansion. This paper presents test results of the second-generation wet turboexpander for the Nuclotron helium refrigerators. A rotor is fixed vertically by a combination of gas and hydrostatic oil bearings. The turbines are capable to operate at a speed of 300,000 revolutions per minute. The power generated by the turbine goes into friction in the oil bearings. The design of the new wet turboexpander was executed in view of those specific conditions, which arise due to the operation at liquid helium temperature. The application of this new expansion machine increases the efficiency of the Nuclotron helium refrigerators by 25%.

Regenerative sorption compressors for cryogenic refrigeration

NASA Technical Reports Server (NTRS)

Bard, Steven; Jones, Jack A.

1990-01-01

Dramatic efficiency improvements for sorption coolers appear possible with use of compressor heat regeneration techniques. The general theory of sorption compressor heat regeneration is discussed in this paper, and several design concepts are presented. These designs result in long-life, low-vibration cryocoolers that potentially have efficiencies comparable to Stirling refrigerators for 65 to 90 K spacecraft instrument cooling applications.

Methods for understanding super-efficient data envelopment analysis results with an application to hospital inpatient surgery.

PubMed

O'Neill, Liam; Dexter, Franklin

2005-11-01

We compare two techniques for increasing the transparency and face validity of Data Envelopment Analysis (DEA) results for managers at a single decision-making unit: multifactor efficiency (MFE) and non-radial super-efficiency (NRSE). Both methods incorporate the slack values from the super-efficient DEA model to provide a more robust performance measure than radial super-efficiency scores. MFE and NRSE are equivalent for unique optimal solutions and a single output. MFE incorporates the slack values from multiple output variables, whereas NRSE does not. MFE can be more transparent to managers since it involves no additional optimization steps beyond the DEA, whereas NRSE requires several. We compare results for operating room managers at an Iowa hospital evaluating its growth potential for multiple surgical specialties. In addition, we address the problem of upward bias of the slack values of the super-efficient DEA model.

Entanglement enhances cooling in microscopic quantum refrigerators.

PubMed

Brunner, Nicolas; Huber, Marcus; Linden, Noah; Popescu, Sandu; Silva, Ralph; Skrzypczyk, Paul

2014-03-01

Small self-contained quantum thermal machines function without external source of work or control but using only incoherent interactions with thermal baths. Here we investigate the role of entanglement in a small self-contained quantum refrigerator. We first show that entanglement is detrimental as far as efficiency is concerned-fridges operating at efficiencies close to the Carnot limit do not feature any entanglement. Moving away from the Carnot regime, we show that entanglement can enhance cooling and energy transport. Hence, a truly quantum refrigerator can outperform a classical one. Furthermore, the amount of entanglement alone quantifies the enhancement in cooling.

Refrigeration of rainbow trout gametes and embryos.

PubMed

Babiak, Igor; Dabrowski, Konrad

2003-12-01

Prolonged access to early embryos composed of undifferentiated, totipotent blastomeres is desirable in situations when multiple collections of gametes are not possible. The objective of the present study is to examine whether the refrigeration of rainbow trout Oncorhynchus mykiss gametes and early embryos would be a suitable, reliable, and efficient tool for prolonging the availability of early developmental stages up to the advanced blastula stage. The study was conducted continuously during fall, winter, and spring spawning seasons. In all, more than 500 experimental variants were performed involving individual samples from 26 females and 33 males derived from three strains. These strains represented three possible circumstances. In optimal one, gametes from good quality donors were obtained soon after ovulation. In the two non-optimal sources, either donors were of poor genetic quality or gametes were collected from a distant location and transported as unfertilized gametes. A highly significant effect of variability of individual sample quality on efficiency of gamete and embryo refrigeration was revealed. The source of gametes significantly affected viability of refrigerated oocytes and embryos, but not spermatozoa. On average, oocytes from optimal source retained full fertilization viability for seven days of chilled storage, significantly longer than from non-optimal sources. Spermatozoa, regardless of storage method, retained full fertilization ability for the first week of storage. Refrigeration of embryos at 1.4+/-0.4 degrees C significantly slowed the development. Two- week-old embryos were still in blastula stage. Average survival rate of embryos refrigerated for 10 days and then transferred to regular incubation temperatures of 9-14 degrees C was 92% in optimal and 51 and 71% in non-optimal source variants. No effect of gamete and embryo refrigeration on the occurrence of developmental abnormalities was observed. Cumulative refrigeration of oocytes and embryos resulted in an average embryo survival rate of 71% in optimal source variants after 17 days of refrigeration (7 days oocytes+10 days embryos). The study shows that both gamete and embryo refrigeration can be successfully used as an efficient tool for prolonging availability of rainbow trout embryos in early developmental stages. Copyright 2003 Wiley-Liss, Inc.

Triple-effect absorption refrigeration system with double-condenser coupling

DOEpatents

DeVault, R.C.; Biermann, W.J.

1993-04-27

A triple effect absorption refrigeration system is provided with a double-condenser coupling and a parallel or series circuit for feeding the refrigerant-containing absorbent solution through the high, medium, and low temperature generators utilized in the triple-effect system. The high temperature condenser receiving vaporous refrigerant from the high temperature generator is double coupled to both the medium temperature generator and the low temperature generator to enhance the internal recovery of heat within the system and thereby increase the thermal efficiency thereof.

Triple-effect absorption refrigeration system with double-condenser coupling

DOEpatents

DeVault, Robert C.; Biermann, Wendell J.

1993-01-01

A triple effect absorption refrigeration system is provided with a double-condenser coupling and a parallel or series circuit for feeding the refrigerant-containing absorbent solution through the high, medium, and low temperature generators utilized in the triple-effect system. The high temperature condenser receiving vaporous refrigerant from the high temperature generator is double coupled to both the medium temperature generator and the low temperature generator to enhance the internal recovery of heat within the system and thereby increase the thermal efficiency thereof.

Sorption cryogenic refrigeration - Status and future

NASA Technical Reports Server (NTRS)

Jones, Jack A.

1988-01-01

The operation principles of sorption cryogenic refrigeration are discussed. Sorption refrigerators have virtually no wear-related moving parts, have negligible vibration, and offer extremely long life (at least ten years), making it possible to obtain efficient, long life and low vibration cooling to as low as 7 K for cryogenic sensors. The physisorption and chemisorption systems recommended for various cooling ranges down to 7 K are described in detail. For long-life cooling at 4-5 K temperatures, a hybrid chemisorption-mechanical refrigeration system is recommended.

COP improvement of refrigerator/freezers, air-conditioners, and heat pumps using nonazeotropic refrigerant mixtures

NASA Technical Reports Server (NTRS)

Westra, Douglas G.

1993-01-01

With the February, 1992 announcement by President Bush to move the deadline for outlawing CFC (chloro-fluoro-carbon) refrigerants from the year 2000 to the year 1996, the refrigeration and air-conditioning industries have been accelerating their efforts to find alternative refrigerants. Many of the alternative refrigerants being evaluated require synthetic lubricants, are less efficient, and have toxicity problems. One option to developing new, alternative refrigerants is to combine existing non-CFC refrigerants to form a nonazeotropic mixture, with the concentration optimized for the given application so that system COP (Coefficient Of Performance) may be maintained or even improved. This paper will discuss the dilemma that industry is facing regarding CFC phase-out and the problems associated with CFC alternatives presently under development. A definition of nonazeotropic mixtures will be provided, and the characteristics and COP benefits of nonazeotropic refrigerant mixtures will be explained using thermodynamic principles. Limitations and disadvantages of nonazeotropic mixtures will be discussed, and example systems using such mixtures will be reviewed.

Evaluation of absorption cycle for space station environmental control system application

NASA Technical Reports Server (NTRS)

Sims, W. H.; Oneill, M. J.; Reid, H. C.; Bisenius, P. M.

1972-01-01

The study to evaluate an absorption cycle refrigeration system to provide environmental control for the space stations is reported. A zero-gravity liquid/vapor separator was designed and tested. The results were used to design a light-weight, efficient generator for the absorption refrigeration system. It is concluded that absorption cycle refrigeration is feasible for providing space station environmental control.

Combined cold compressor/ejector helium refrigerator

DOEpatents

Brown, D.P.

1984-06-05

A refrigeration apparatus having an ejector operatively connected with a cold compressor to form a two-stage pumping system. This pumping system is used to lower the pressure, and thereby the temperature of a bath of boiling refrigerant (helium). The apparatus as thus arranged and operated has substantially improved operating efficiency when compared to other processes or arrangements for achieving a similar low pressure.

Combined cold compressor/ejector helium refrigerator

DOEpatents

Brown, Donald P.

1985-01-01

A refrigeration apparatus having an ejector operatively connected with a cold compressor to form a two-stage pumping system. This pumping system is used to lower the pressure, and thereby the temperature of a bath of boiling refrigerant (helium). The apparatus as thus arranged and operated has substantially improved operating efficiency when compared to other processes or arrangements for achieving a similar low pressure.

Magnetic-Flux-Compression Cooling Using Superconductors

NASA Technical Reports Server (NTRS)

Strayer, Donald M.; Israelsson, Ulf E.; Elleman, Daniel D.

1989-01-01

Proposed magnetic-flux-compression refrigeration system produces final-stage temperatures below 4.2 K. More efficient than mechanical and sorption refrigerators at temperatures in this range. Weighs less than comparable liquid-helium-cooled superconducting magnetic refrigeration systems operating below 4.2 K. Magnetic-flux-compression cooling stage combines advantages of newly discovered superconductors with those of cooling by magnetization and demagnetization of paramagnetic salts.

Optimal coupling and feasibility of a solar-powered year-round ejector air conditioner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sokolov, M.; Hershgal, D.

1993-06-01

An ejector refrigeration system that uses a conventional refrigerant (R-114) is introduced as a possible mechanism for providing solar-based air-conditioning. Optimal coupling conditions between the collectors' energy output and energy requirements of the cooling system, are investigated. Operation at such optimal conditions assures maximized overall efficiency. Procedures leading to the evaluation of the performance of a real system are disclosed. Design curves for such a system with R-114 as refrigerant are provided. A multi-ejectors arrangement that provides an efficient adjustment for variations of ambient conditions, is described. Year-round air-conditioning is facilitated by rerouting the refrigerant flow through a heating modemore » of the system. Calculations are carried out for illustrative configurations in which relatively low condensing temperature (water reservoirs, cooling towers, or moderate climate) can be maintained.« less

The effect of coolants on the performance of magnetic micro-refrigerators.

PubMed

Silva, D J; Bordalo, B D; Pereira, A M; Ventura, J; Oliveira, J C R E; Araújo, J P

2014-06-01

Magnetic refrigeration is an alternative cooling technique with envisaged technological applications on micro- and opto-electronic devices. Here, we present a magnetic micro-refrigerator cooling device with embedded micro-channels and based on the magnetocaloric effect. We studied the influence of the coolant fluid in the refrigeration process by numerically simulating the heat transfer processes using the finite element method. This allowed us to calculate the cooling power of the device. Our results show that gallium is the most efficient coolant fluid and, when used with Gd5Si2Ge2, a maximum power of 11.2 W/mm3 at a working frequency of -5 kHz can be reached. However, for operation frequencies around 50 Hz, water is the most efficient fluid with a cooling power of 0.137 W/mm3.

Active magnetic refrigerants based on Gd-Si-Ge material and refrigeration apparatus and process

DOEpatents

Gschneidner, Jr., Karl A.; Pecharsky, Vitalij K.

1998-04-28

Active magnetic regenerator and method using Gd.sub.5 (Si.sub.x Ge.sub.1-x).sub.4, where x is equal to or less than 0.5, as a magnetic refrigerant that exhibits a reversible ferromagnetic/antiferromagnetic or ferromagnetic-II/ferromagnetic-I first order phase transition and extraordinary magneto-thermal properties, such as a giant magnetocaloric effect, that renders the refrigerant more efficient and useful than existing magnetic refrigerants for commercialization of magnetic regenerators. The reversible first order phase transition is tunable from approximately 30 K to approximately 290 K (near room temperature) and above by compositional adjustments. The active magnetic regenerator and method can function for refrigerating, air conditioning, and liquefying low temperature cryogens with significantly improved efficiency and operating temperature range from approximately 10 K to 300 K and above. Also an active magnetic regenerator and method using Gd.sub.5 (Si.sub.x Ge.sub.1-x).sub.4, where x is equal to or greater than 0.5, as a magnetic heater/refrigerant that exhibits a reversible ferromagnetic/paramagnetic second order phase transition with large magneto-thermal properties, such as a large magnetocaloric effect that permits the commercialization of a magnetic heat pump and/or refrigerant. This second order phase transition is tunable from approximately 280 K (near room temperature) to approximately 350 K by composition adjustments. The active magnetic regenerator and method can function for low level heating for climate control for buildings, homes and automobile, and chemical processing.

Active magnetic refrigerants based on Gd-Si-Ge material and refrigeration apparatus and process

DOEpatents

Gschneidner, K.A. Jr.; Pecharsky, V.K.

1998-04-28

Active magnetic regenerator and method using Gd{sub 5} (Si{sub x}Ge{sub 1{minus}x}){sub 4}, where x is equal to or less than 0.5, as a magnetic refrigerant that exhibits a reversible ferromagnetic/antiferromagnetic or ferromagnetic-II/ferromagnetic-I first order phase transition and extraordinary magneto-thermal properties, such as a giant magnetocaloric effect, that renders the refrigerant more efficient and useful than existing magnetic refrigerants for commercialization of magnetic regenerators. The reversible first order phase transition is tunable from approximately 30 K to approximately 290 K (near room temperature) and above by compositional adjustments. The active magnetic regenerator and method can function for refrigerating, air conditioning, and liquefying low temperature cryogens with significantly improved efficiency and operating temperature range from approximately 10 K to 300 K and above. Also an active magnetic regenerator and method using Gd{sub 5} (Si{sub x} Ge{sub 1{minus}x}){sub 4}, where x is equal to or greater than 0.5, as a magnetic heater/refrigerant that exhibits a reversible ferromagnetic/paramagnetic second order phase transition with large magneto-thermal properties, such as a large magnetocaloric effect that permits the commercialization of a magnetic heat pump and/or refrigerant. This second order phase transition is tunable from approximately 280 K (near room temperature) to approximately 350 K by composition adjustments. The active magnetic regenerator and method can function for low level heating for climate control for buildings, homes and automobile, and chemical processing. 27 figs.

Commissioning and Operational Experience with 1 kW Class Helium Refrigerator/Liquefier for SST-1

NASA Astrophysics Data System (ADS)

Dhard, C. P.; Sarkar, B.; Misra, Ruchi; Sahu, A. K.; Tanna, V. L.; Tank, J.; Panchal, P.; Patel, J. C.; Phadke, G. D.; Saxena, Y. C.

2004-06-01

The helium refrigerator/liquefier (R/L) for the Steady State Super conducting Tokamak (SST-1) has been developed with very stringent specifications for the different operational modes. The total refrigeration capacity is 650 W at 4.5 K and liquefaction capacity of 200 l/h. A cold circulation pump is used for the forced flow cooling of 300 g/s supercritical helium (SHe) for the magnet system (SCMS). The R/L has been designed also to absorb a 200 W transient heat load of the SCMS. The plant consists of a compressor station, oil removal system, on-line purifier, Main Control Dewar (MCD) with associated heat exchangers, cold circulation pump and warm gas management system. An Integrated Flow Control and Distribution System (IFDCS) has been designed, fabricated and installed for distribution of SHe in the toroidal and poloidal field coils as well as liquid helium for cooling of 10 pairs of current leads. A SCADA based control system has been designed using PLC for R/L as well as IFDCS. The R/L has been commissioned and required parameters were achieved confirming to the process. All the test results and commissioning experiences are discussed in this paper.

Comparison of HFC-134a and the ternary blend, Suva MP39, as replacements for the refrigerant, CGC-12

NASA Astrophysics Data System (ADS)

Fletcher, Lyn E.

1993-09-01

The refrigerant gas CFC-12 has been widely used in Royal Australian Navy (RAN) equipment. With the Montreal protocol phase-out of this and other ozone depleting substances, alternative refrigerant gases must be identified. These replacements would ideally have the same efficiency as CFC-12, cause no health and safety risks and allow changeover to proceed with minimal costs. This paper reviews the attributes of two refrigerant gases, HFC-134a and Suva MP39, which are being considered by the RAN.

Displacer Diameter Effect in Displacer Pulse Tube Refrigerator

NASA Astrophysics Data System (ADS)

Zhu, Shaowei

2017-12-01

Gas driving displacer pulse tube refrigerators are one of the work recovery type of pulse tube refrigerators whose theoretical efficiency is the same as Stirling refrigerators'. Its cooling power is from the displacement of the displacer. Displace diameter, rod diameter and pressure drop of the regenerator influence the displacement, which are investigated by numerical simulation. It is shown that the displacement ratio of the displacer over the piston is almost not affected by the displacer diameter at the same rod diameter ratio, or displacer with different diameters almost has the same performance.

High-Performance, Low Environmental Impact Refrigerants

NASA Technical Reports Server (NTRS)

McCullough, E. T.; Dhooge, P. M.; Glass, S. M.; Nimitz, J. S.

2001-01-01

Refrigerants used in process and facilities systems in the US include R-12, R-22, R-123, R-134a, R-404A, R-410A, R-500, and R-502. All but R-134a, R-404A, and R-410A contain ozone-depleting substances that will be phased out under the Montreal Protocol. Some of the substitutes do not perform as well as the refrigerants they are replacing, require new equipment, and have relatively high global warming potentials (GWPs). New refrigerants are needed that addresses environmental, safety, and performance issues simultaneously. In efforts sponsored by Ikon Corporation, NASA Kennedy Space Center (KSC), and the US Environmental Protection Agency (EPA), ETEC has developed and tested a new class of refrigerants, the Ikon (registered) refrigerants, based on iodofluorocarbons (IFCs). These refrigerants are nonflammable, have essentially zero ozone-depletion potential (ODP), low GWP, high performance (energy efficiency and capacity), and can be dropped into much existing equipment.

Magnetic refrigeration for low-temperature applications

NASA Technical Reports Server (NTRS)

Barclay, J. A.

1985-01-01

The application of refrigeration at low temperatures ranging from production of liquid helium for medical imaging systems to cooling of infrared sensors on surveillance satellites is discussed. Cooling below about 15 K with regenerative refrigerators is difficult because of the decreasing thermal mass of the regenerator compared to that of the working material. In order to overcome this difficulty with helium gas as the working material, a heat exchanger plus a Joule-Thomson or other exponder is used. Regenerative magnetic refrigerators with magnetic solids as the working material have the same regenerator problem as gas refrigerators. This problem provides motivation for the development of nonregenerative magnetic refrigerators that span approximately 1 K to approximately 0 K. Particular emphasis is placed on high reliability and high efficiency. Calculations indicate considerable promise in this area. The principles, the potential, the problems, and the progress towards development of successful 4 to 20 K magnetic refrigerators are discussed.

An improved wave rotor refrigerator using an outside gas flow for recycling the expansion work

NASA Astrophysics Data System (ADS)

Zhao, J.; Hu, D.

2017-03-01

To overcome the bottleneck of traditional gas wave refrigeration, an improved wave rotor refrigerator (WRR) cycle has been proposed, in which the expansion work was recycled during the process of refrigeration. Thermodynamic analysis of the two cycles shows that the refrigeration efficiency of the improved WRR cycle has been greatly increased compared with the traditional WRR. The performance of an improved WRR was investigated by adjusting the major operational parameters, such as the rotational speed of the wave rotor, port size, and inflow overpressure. The experimental results show that pressure loss can be reduced by nearly 40 % in this improved refrigeration system. Meanwhile, a two-dimensional numerical simulation was performed to understand the wave interactions that take place inside the rotor channels.

76 FR 59394 - Energy Conservation Program for Consumer Products: Publication of the Extension of Interim Waiver...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-26

... Electronics America, Inc. From the Department of Energy Residential Refrigerator and Refrigerator-Freezer Test... Electronics America, Inc. (Samsung) from energy efficiency test procedure requirements that are applicable to...

Neon turbo-Brayton cycle refrigerator for HTS power machines

NASA Astrophysics Data System (ADS)

Hirai, Hirokazu; Hirokawa, M.; Yoshida, Shigeru; Nara, N.; Ozaki, S.; Hayashi, H.; Okamoto, H.; Shiohara, Y.

2012-06-01

We developed a prototype turbo-Brayton refrigerator whose working fluid is neon gas. The refrigerator is designed for a HTS (High Temperature Superconducting) power transformer and its cooling power is more than 2 kW at 65 K. The refrigerator has a turboexpander and a turbo-compressor, which utilize magnetic bearings. These rotational machines have no rubbing parts and no oil-components. Those make a long maintenance interval of the refrigerator. The refrigerator is very compact because our newly developed turbo-compressor is volumetrically smaller than a displacement type compressor in same operating specification. Another feature of the refrigerator is a wide range operation capability for various heat-loads. Cooling power is controlled by the input-power of the turbo-compressor instead of the conventional method of using an electric heater. The rotational speed of the compressor motor is adjusted by an inverter. This system is expected to be more efficient. We show design details, specification and cooling test results of the new refrigerator in this paper.

Limited options for low-global-warming-potential refrigerants.

PubMed

McLinden, Mark O; Brown, J Steven; Brignoli, Riccardo; Kazakov, Andrei F; Domanski, Piotr A

2017-02-17

Hydrofluorocarbons, currently used as refrigerants in air-conditioning systems, are potent greenhouse gases, and their contribution to climate change is projected to increase. Future use of the hydrofluorocarbons will be phased down and, thus replacement fluids must be found. Here we show that only a few pure fluids possess the combination of chemical, environmental, thermodynamic, and safety properties necessary for a refrigerant and that these fluids are at least slightly flammable. We search for replacements by applying screening criteria to a comprehensive chemical database. For the fluids passing the thermodynamic and environmental screens (critical temperature and global warming potential), we simulate performance in small air-conditioning systems, including optimization of the heat exchangers. We show that the efficiency-versus-capacity trade-off that exists in an ideal analysis disappears when a more realistic system is considered. The maximum efficiency occurs at a relatively high volumetric refrigeration capacity, but there are few fluids in this range.

Limited options for low-global-warming-potential refrigerants

NASA Astrophysics Data System (ADS)

McLinden, Mark O.; Brown, J. Steven; Brignoli, Riccardo; Kazakov, Andrei F.; Domanski, Piotr A.

2017-02-01

Hydrofluorocarbons, currently used as refrigerants in air-conditioning systems, are potent greenhouse gases, and their contribution to climate change is projected to increase. Future use of the hydrofluorocarbons will be phased down and, thus replacement fluids must be found. Here we show that only a few pure fluids possess the combination of chemical, environmental, thermodynamic, and safety properties necessary for a refrigerant and that these fluids are at least slightly flammable. We search for replacements by applying screening criteria to a comprehensive chemical database. For the fluids passing the thermodynamic and environmental screens (critical temperature and global warming potential), we simulate performance in small air-conditioning systems, including optimization of the heat exchangers. We show that the efficiency-versus-capacity trade-off that exists in an ideal analysis disappears when a more realistic system is considered. The maximum efficiency occurs at a relatively high volumetric refrigeration capacity, but there are few fluids in this range.

Current fluctuations in quantum absorption refrigerators

NASA Astrophysics Data System (ADS)

Segal, Dvira

2018-05-01

Absorption refrigerators transfer thermal energy from a cold bath to a hot bath without input power by utilizing heat from an additional "work" reservoir. Particularly interesting is a three-level design for a quantum absorption refrigerator, which can be optimized to reach the maximal (Carnot) cooling efficiency. Previous studies of three-level chillers focused on the behavior of the averaged cooling current. Here, we go beyond that and study the full counting statistics of heat exchange in a three-level chiller model. We explain how to obtain the complete cumulant generating function of the refrigerator in a steady state, then derive a partial cumulant generating function, which yields closed-form expressions for both the averaged cooling current and its noise. Our analytical results and simulations are beneficial for the design of nanoscale engines and cooling systems far from equilibrium, with their performance optimized according to different criteria, efficiency, power, fluctuations, and dissipation.

Quantum Stirling heat engine and refrigerator with single and coupled spin systems

NASA Astrophysics Data System (ADS)

Huang, Xiao-Li; Niu, Xin-Ya; Xiu, Xiao-Ming; Yi, Xue-Xi

2014-02-01

We study the reversible quantum Stirling cycle with a single spin or two coupled spins as the working substance. With the single spin as the working substance, we find that under certain conditions the reversed cycle of a heat engine is NOT a refrigerator, this feature holds true for a Stirling heat engine with an ion trapped in a shallow potential as its working substance. The efficiency of quantum Stirling heat engine can be higher than the efficiency of the Carnot engine, but the performance coefficient of the quantum Stirling refrigerator is always lower than its classical counterpart. With two coupled spins as the working substance, we find that a heat engine can turn to a refrigerator due to the increasing of the coupling constant, this can be explained by the properties of the isothermal line in the magnetic field-entropy plane.

Limited options for low-global-warming-potential refrigerants

PubMed Central

McLinden, Mark O.; Brown, J. Steven; Brignoli, Riccardo; Kazakov, Andrei F.; Domanski, Piotr A.

2017-01-01

Hydrofluorocarbons, currently used as refrigerants in air-conditioning systems, are potent greenhouse gases, and their contribution to climate change is projected to increase. Future use of the hydrofluorocarbons will be phased down and, thus replacement fluids must be found. Here we show that only a few pure fluids possess the combination of chemical, environmental, thermodynamic, and safety properties necessary for a refrigerant and that these fluids are at least slightly flammable. We search for replacements by applying screening criteria to a comprehensive chemical database. For the fluids passing the thermodynamic and environmental screens (critical temperature and global warming potential), we simulate performance in small air-conditioning systems, including optimization of the heat exchangers. We show that the efficiency-versus-capacity trade-off that exists in an ideal analysis disappears when a more realistic system is considered. The maximum efficiency occurs at a relatively high volumetric refrigeration capacity, but there are few fluids in this range. PMID:28211518

Control system for thermoelectric refrigerator

NASA Technical Reports Server (NTRS)

Nelson, John L. (Inventor); Criscuolo, Lance (Inventor); Gilley, Michael D. (Inventor); Park, Brian V. (Inventor)

1996-01-01

Apparatus including a power supply (202) and control system is provided for maintaining the temperature within an enclosed structure (40) using thermoelectric devices (92). The apparatus may be particularly beneficial for use with a refrigerator (20) having superinsulation materials (46) and phase change materials (112) which cooperate with the thermoelectric device (92) to substantially enhance the overall operating efficiency of the refrigerator (20). The electrical power supply (202) and control system allows increasing the maximum power capability of the thermoelectric device (92) in response to increased heat loads within the refrigerator (20). The electrical power supply (202) and control system may also be used to monitor the performance of the cooling system (70) associated with the refrigerator (20).

Experimental investigation of an alternating evaporator duty refrigerator/freezer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lavanis, M.; Haider, I.; Radermacher, R.

1998-12-31

A bistable solenoid valve has been used to build an alternating evaporator duty (AED) domestic refrigerator/freezer. This refrigerator has two vapor compression refrigeration loops that share a common compressor, condenser, and suction line heat exchanger. Each of the refrigeration loops has an expansion device and evaporator. One evaporator is located in the fresh food compartment and the other is located in the freezer compartment. The bistable solenoid valve directs the flow of the refrigerant through one loop at a time. Only one of the two compartments is cooled at any given time. With this configuration, the food compartment is cooledmore » at a higher evaporator temperature than the freezer. Due to this, the energy efficiency of the refrigerator is improved by 8.5% over a conventional domestic refrigerator/freezer. Also, this cycle allows for completely independent temperature control of the freezer and fresh food compartments. There may be a penalty because this cycle does not allow for both loops to be simultaneously optimized. Isobutane was the only refrigerant used in this investigation.« less

Thermodynamic analysis of cascade microcryocoolers with low pressure ratios

DOE Office of Scientific and Technical Information (OSTI.GOV)

Radebaugh, Ray

2014-01-29

The vapor-compression cycle for refrigeration near ambient temperature achieves high efficiency because the isenthalpic expansion of the condensed liquid is a rather efficient process. However, temperatures are limited to about 200 K with a single-stage system. Temperatures down to 77 K are possible with many stages. In the case of microcryocoolers using microcompressors, pressure ratios are usually limited to about 6 or less. As a result, even more stages are required to reach 77 K. If the microcompressors can be fabricated with low-cost wafer-level techniques, then the use of many stages with separate compressors may become a viable option formore » achieving temperatures of 77 K with high efficiency. We analyze the ideal thermodynamic efficiency of a cascade Joule-Thomson system for various temperatures down to 77 K and with low pressure ratios. About nine stages are required for 77 K, but fewer stages are also analyzed for operation at higher temperatures. For 77 K, an ideal second-law efficiency of 83 % of Carnot is possible with perfect recuperative heat exchangers and 65 % of Carnot is possible with no recuperative heat exchangers. The results are compared with calculated efficiencies in mixed-refrigerant cryocoolers over the range of 77 K to 200 K. Refrigeration at intermediate temperatures is also available. The use of single-component fluids in each of the stages is expected to eliminate the problem of pulsating flow and temperature oscillations experienced in microcryocoolers using mixed refrigerants.« less

High temperature refrigerator

DOEpatents

Steyert, Jr., William A.

1978-01-01

A high temperature magnetic refrigerator which uses a Stirling-like cycle in which rotating magnetic working material is heated in zero field and adiabatically magnetized, cooled in high field, then adiabatically demagnetized. During this cycle said working material is in heat exchange with a pumped fluid which absorbs heat from a low temperature heat source and deposits heat in a high temperature reservoir. The magnetic refrigeration cycle operates at an efficiency 70% of Carnot.

REVIEW OF ENERGY EFFICIENCY OF REFRIGERATOR/FREEZER GASKETS

EPA Science Inventory

The report gives results of an investigation of the significance of heat leakage through gaskets in household refrigerator/freezers, explores different design features, and suggests further study if necessary. he report gives results of an extensive literature review, interviews ...

REVIEW OF ENERGY EFFICIENCY OF REFRIGERATOR/FREEZER GASKETS

EPA Science Inventory

The report gives results of an investigation of the significance of heat leakage through gaskets in household refrigerator/freezers, explores different design features, and suggests further study if necessary. The report gives results of an extensive literature review, interviews...

Heat exchanger-accumulator

DOEpatents

Ecker, Amir L.

1980-01-01

What is disclosed is a heat exchanger-accumulator for vaporizing a refrigerant or the like, characterized by an upright pressure vessel having a top, bottom and side walls; an inlet conduit eccentrically and sealingly penetrating through the top; a tubular overflow chamber disposed within the vessel and sealingly connected with the bottom so as to define an annular outer volumetric chamber for receiving refrigerant; a heat transfer coil disposed in the outer volumetric chamber for vaporizing the liquid refrigerant that accumulates there; the heat transfer coil defining a passageway for circulating an externally supplied heat exchange fluid; transferring heat efficiently from the fluid; and freely allowing vaporized refrigerant to escape upwardly from the liquid refrigerant; and a refrigerant discharge conduit penetrating sealingly through the top and traversing substantially the length of the pressurized vessel downwardly and upwardly such that its inlet is near the top of the pressurized vessel so as to provide a means for transporting refrigerant vapor from the vessel. The refrigerant discharge conduit has metering orifices, or passageways, penetrating laterally through its walls near the bottom, communicating respectively interiorly and exteriorly of the overflow chamber for controllably carrying small amounts of liquid refrigerant and oil to the effluent stream of refrigerant gas.

Helium refrigerator maintenance and reliability at the OPAL cold neutron source

NASA Astrophysics Data System (ADS)

Thiering, Russell; Taylor, David; Lu, Weijian

2012-06-01

Australia's first Cold Neutron Source (CNS) is a major asset to its nuclear research program. The CNS, and associated helium refrigerator, was commissioned in 2006 and is operated at the Open Pool Light Water nuclear Reactor (OPAL). The OPAL CNS operates a 20K, 5 kW Brayton cycle helium refrigerator. In this paper relevant experiences from helium refrigerator operation, maintenance and repair are presented along with the lessons learnt from a series of technical investigations. Turbine failure, due to volatile organic species, is discussed along with the related compressor oil degradation and oil separation efficiency.

Space shuttle orbiter mechanical refrigeration system

NASA Technical Reports Server (NTRS)

Williams, J. L.

1974-01-01

A radiator/condenser was designed which is efficient in both condensation (refrigeration) and liquid phase (radiator) operating modes, including switchover from the refrigeration mode to the radiator mode and vice versa. A method for predicting the pressure drop of a condensing two-phase flow in zero-gravity was developed along with a method for predicting the flow regime which would prevail along the condensation path. The hybrid refrigeration system was assembled with the two radiator/condenser panels installed in a space environment simulator. The system was tested under both atmospheric and vacuum conditions. Results of the tests are presented.

Overview of Air Liquide refrigeration systems between 1.8 K and 200 K

NASA Astrophysics Data System (ADS)

Gondrand, C.; Durand, F.; Delcayre, F.; Crispel, S.; Baguer, G. M. Gistau

2014-01-01

Cryogenic refrigeration systems are necessary for numerous applications. Gas purification and distillation require temperatures between 15 K and 200 K depending on the application, space simulation chambers down to 15 K, superconductivity between 1.8 K and up to 75 K (magnets, cavities or HTS devices like cables, FCL, SMES, etc), Cold Neutron Sources between 15 and 20 K, etc. Air Liquide Advanced Technologies is designing and manufacturing refrigerators since 60 years to satisfy those needs. The step by step developments achieved have led to machines with higher efficiency and reliability. In 1965, reciprocating compressors and Joule Thomson expansion valves were used. In 1969, centripetal expanders began to be used. In 1980, oil lubricated screw compressors took the place of reciprocating compressors and a standard range of Claude cycle refrigerators was developed: the HELIAL series. 1980 was also the time for cryogenic centrifugal compressor development. In 2011, driven by the need for lower operational cost (high efficiency and low maintenance), cycle oil free centrifugal compressors on magnetic bearings were introduced instead of screw compressors. The power extracted by centripetal expanders was recovered. Based on this technology, a range of Turbo-Brayton refrigerators has been designed for temperatures between 40 K and 150 K. On-going development will enable widening the range of Turbo-Brayton refrigerators to cryogenic temperatures down to 15 K.. Cryogenic centrifugal circulators have been developed in order to answer to an increasing demand of 4 K refrigerators able to distribute cold power.

Overview of Air Liquide refrigeration systems between 1.8 K and 200 K

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gondrand, C.; Durand, F.; Delcayre, F.

Cryogenic refrigeration systems are necessary for numerous applications. Gas purification and distillation require temperatures between 15 K and 200 K depending on the application, space simulation chambers down to 15 K, superconductivity between 1.8 K and up to 75 K (magnets, cavities or HTS devices like cables, FCL, SMES, etc), Cold Neutron Sources between 15 and 20 K, etc. Air Liquide Advanced Technologies is designing and manufacturing refrigerators since 60 years to satisfy those needs. The step by step developments achieved have led to machines with higher efficiency and reliability. In 1965, reciprocating compressors and Joule Thomson expansion valves weremore » used. In 1969, centripetal expanders began to be used. In 1980, oil lubricated screw compressors took the place of reciprocating compressors and a standard range of Claude cycle refrigerators was developed: the HELIAL series. 1980 was also the time for cryogenic centrifugal compressor development. In 2011, driven by the need for lower operational cost (high efficiency and low maintenance), cycle oil free centrifugal compressors on magnetic bearings were introduced instead of screw compressors. The power extracted by centripetal expanders was recovered. Based on this technology, a range of Turbo-Brayton refrigerators has been designed for temperatures between 40 K and 150 K. On-going development will enable widening the range of Turbo-Brayton refrigerators to cryogenic temperatures down to 15 K.. Cryogenic centrifugal circulators have been developed in order to answer to an increasing demand of 4 K refrigerators able to distribute cold power.« less

Unified trade-off optimization for general heat devices with nonisothermal processes.

PubMed

Long, Rui; Liu, Wei

2015-04-01

An analysis of the efficiency and coefficient of performance (COP) for general heat engines and refrigerators with nonisothermal processes is conducted under the trade-off criterion. The specific heat of the working medium has significant impacts on the optimal configurations of heat devices. For cycles with constant specific heat, the bounds of the efficiency and COP are found to be the same as those obtained through the endoreversible Carnot ones. However, they are independent of the cycle time durations. For cycles with nonconstant specific heat, whose dimensionless contact time approaches infinity, the general alternative upper and lower bounds of the efficiency and COP under the trade-off criteria have been proposed under the asymmetric limits. Furthermore, when the dimensionless contact time approaches zero, the endoreversible Carnot model is recovered. In addition, the efficiency and COP bounds of different kinds of actual heat engines and refrigerators have also been analyzed. This paper may provide practical insight for designing and operating actual heat engines and refrigerators.

Qubit absorption refrigerator at strong coupling

NASA Astrophysics Data System (ADS)

Mu, Anqi; Agarwalla, Bijay Kumar; Schaller, Gernot; Segal, Dvira

2017-12-01

We demonstrate that a quantum absorption refrigerator (QAR) can be realized from the smallest quantum system, a qubit, by coupling it in a non-additive (strong) manner to three heat baths. This function is un-attainable for the qubit model under the weak system-bath coupling limit, when the dissipation is additive. In an optimal design, the reservoirs are engineered and characterized by a single frequency component. We then obtain closed expressions for the cooling window and refrigeration efficiency, as well as bounds for the maximal cooling efficiency and the efficiency at maximal power. Our results agree with macroscopic designs and with three-level models for QARs, which are based on the weak system-bath coupling assumption. Beyond the optimal limit, we show with analytical calculations and numerical simulations that the cooling efficiency varies in a non-universal manner with model parameters. Our work demonstrates that strongly-coupled quantum machines can exhibit function that is un-attainable under the weak system-bath coupling assumption.

Progress towards Managing Residential Electricity Demand: Impacts of Standards and Labeling for Refrigerators and Air Conditioners in India

DOE Office of Scientific and Technical Information (OSTI.GOV)

McNeil, Michael A.; Iyer, Maithili

The development of Energy Efficiency Standards and Labeling (EES&L) began in earnest in India in 2001 with the Energy Conservation Act and the establishment of the Indian Bureau of Energy Efficiency (BEE). The first main residential appliance to be targeted was refrigerators, soon to be followed by room air conditioners. Both of these appliances are of critical importance to India's residential electricity demand. About 15percent of Indian households own a refrigerator, and sales total about 4 million per year, but are growing. At the same time, the Indian refrigerator market has seen a strong trend towards larger and more consumptivemore » frost-free units. Room air conditioners in India have traditionally been sold to commercial sector customers, but an increasing number are going to the residential sector. Room air conditioner sales growth in India peaked in the last few years at 20percent per year. In this paper, we perform an engineering-based analysis using data specific to Indian appliances. We evaluate costs and benefits to residential and commercial sector consumers from increased equipment costs and utility bill savings. The analysis finds that, while the BEE scheme presents net benefits to consumers, there remain opportunities for efficiency improvement that would optimize consumer benefits, according to Life Cycle Cost analysis. Due to the large and growing market for refrigerators and air conditioners in India, we forecast large impacts from the standards and labeling program as scheduled. By 2030, this program, if fully implemented would reduce Indian residential electricity consumption by 55 TWh. Overall savings through 2030 totals 385 TWh. Finally, while efficiency levels have been set for several years for refrigerators, labels and MEPS for these products remain voluntary. We therefore consider the negative impact of this delay of implementation to energy and financial savings achievable by 2030.« less

Responses of Super Rice (Oryza sativa L.) to Different Planting Methods for Grain Yield and Nitrogen-Use Efficiency in the Single Cropping Season

PubMed Central

Chen, Song; Wang, Danying; Xu, Chunmei; Ji, Chenglin; Zhang, Xiaoguo; Zhao, Xia; Zhang, Xiufu; Chauhan, Bhagirath Singh

2014-01-01

To break the yield ceiling of rice production, a super rice project was developed in 1996 to breed rice varieties with super high yield. A two-year experiment was conducted to evaluate yield and nitrogen (N)-use response of super rice to different planting methods in the single cropping season. A total of 17 rice varieties, including 13 super rice and four non-super checks (CK), were grown under three N levels [0 (N0), 150 (N150), and 225 (N225) kg ha−1] and two planting methods [transplanting (TP) and direct-seeding in wet conditions (WDS)]. Grain yield under WDS (7.69 t ha−1) was generally lower than TP (8.58 t ha−1). However, grain yield under different planting methods was affected by N rates as well as variety groups. In both years, there was no difference in grain yield between super and CK varieties at N150, irrespective of planting methods. However, grain yield difference was dramatic in japonica groups at N225, that is, there was an 11.3% and 14.1% average increase in super rice than in CK varieties in WDS and TP, respectively. This suggests that high N input contributes to narrowing the yield gap in super rice varieties, which also indicates that super rice was bred for high fertility conditions. In the japonica group, more N was accumulated in super rice than in CK at N225, but no difference was found between super and CK varieties at N0 and N150. Similar results were also found for N agronomic efficiency. The results suggest that super rice varieties have an advantage for N-use efficiency when high N is applied. The response of super rice was greater under TP than under WDS. The results suggest that the need to further improve agronomic and other management practices to achieve high yield and N-use efficiency for super rice varieties in WDS. PMID:25111805

Responses of super rice (Oryza sativa L.) to different planting methods for grain yield and nitrogen-use efficiency in the single cropping season.

PubMed

Chen, Song; Wang, Danying; Xu, Chunmei; Ji, Chenglin; Zhang, Xiaoguo; Zhao, Xia; Zhang, Xiufu; Chauhan, Bhagirath Singh

2014-01-01

To break the yield ceiling of rice production, a super rice project was developed in 1996 to breed rice varieties with super high yield. A two-year experiment was conducted to evaluate yield and nitrogen (N)-use response of super rice to different planting methods in the single cropping season. A total of 17 rice varieties, including 13 super rice and four non-super checks (CK), were grown under three N levels [0 (N0), 150 (N150), and 225 (N225) kg ha-1] and two planting methods [transplanting (TP) and direct-seeding in wet conditions (WDS)]. Grain yield under WDS (7.69 t ha-1) was generally lower than TP (8.58 t ha-1). However, grain yield under different planting methods was affected by N rates as well as variety groups. In both years, there was no difference in grain yield between super and CK varieties at N150, irrespective of planting methods. However, grain yield difference was dramatic in japonica groups at N225, that is, there was an 11.3% and 14.1% average increase in super rice than in CK varieties in WDS and TP, respectively. This suggests that high N input contributes to narrowing the yield gap in super rice varieties, which also indicates that super rice was bred for high fertility conditions. In the japonica group, more N was accumulated in super rice than in CK at N225, but no difference was found between super and CK varieties at N0 and N150. Similar results were also found for N agronomic efficiency. The results suggest that super rice varieties have an advantage for N-use efficiency when high N is applied. The response of super rice was greater under TP than under WDS. The results suggest that the need to further improve agronomic and other management practices to achieve high yield and N-use efficiency for super rice varieties in WDS.

Effects of storage conditions of Moringa oleifera seeds on its performance in coagulation.

PubMed

Katayon, S; Noor, M J Megat Mohd; Asma, M; Ghani, L A Abdul; Thamer, A M; Azni, I; Ahmad, J; Khor, B C; Suleyman, A M

2006-09-01

Moringa oleifera is a plant whose seeds have coagulation properties for treating water and wastewater. In this study the coagulation efficiency of Moringa oleifera kept in different storage conditions were studied. The Moringa oleifera seeds were stored at different conditions and durations; open container and closed container at room temperature (28 degrees C) and refrigerator (3 degrees C) for durations of 1, 3 and 5 months. Comparison between turbidity removal efficiency of Moringa oleifera kept in refrigerator and room temperature revealed that there was no significant difference between them. The Moringa oleifera kept in refrigerator and room temperature for one month showed higher turbidity removal efficiency, compared to those kept for 3 and 5 months, at both containers. The coagulation efficiency of Moringa oleifera was found to be dependent on initial turbidity of water samples. Highest turbidity removals were obtained for water with very high initial turbidity. In summary coagulation efficiency of Moringa oleifera was found independent of storage temperature and container, however coagulation efficiency of Moringa oleifera decreased as storage duration increased. In addition, Moringa oleifera can be used as a potential coagulant especially for very high turbidity water.

Analysis of Environmentally Friendly Refrigerant Options for Window Air Conditioners

DOE PAGES

Bansal, Pradeep; Shen, Bo

2015-03-12

This paper presents a technical assessment of environmentally friendly refrigerants as alternatives to R410A for window air conditioners. The alternative refrigerants that are studied for its replacement include R32, a mixture of R32/R125 with 90%/10% molar concentration, R600a, R290, R1234yf, R1234ze and R134a. Baseline experiments were performed on a window unit charged with R410A. The heat pump design model (HPDM) was modified and calibrated with the baseline data and was used to evaluate the comparative performance of the WAC with alternative refrigerants. The paper discusses the advantages and disadvantages of each refrigerants and their suitability for window air conditioners. Amongmore » all the refrigerants studied, R32 offers the best efficiency and the lowest Global Warming Potential (GWP), and hence its use will result in the overall environmental friendliness.« less

Analysis of a domestic refrigerator cycle with an ejector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tomasek, M.L.; Radermacher, R.

1995-08-01

In this paper, an improved cooling cycle for a conventional domestic refrigerator-freezer utilizing an ejector for vapor precompression is analyzed using an idealized model Its energy efficiency is compared to that of the conventional refrigerator-freezer system. Emphasis is placed on off-design conditions. The ejector-enhanced refrigeration cycle consists of two evaporators that operate at different pressure and temperature levels. The ejector combines the vapor flows exiting the two evaporators into one at an intermediate pressure level The ejector cycle gives an increase of up to 12.4% in the coefficient of performance (COP) compared to that of a standard refrigerator-freezer refrigeration cycle.more » The analysis includes calculations on the optimum throat diameters of the ejector. The investigation on the off-design performance of the ejector cycle shows little dependency of energy consumption on constant ejector throat diameters.« less

Overview of RICOR tactical cryogenic refrigerators for space missions

NASA Astrophysics Data System (ADS)

Riabzev, Sergey; Filis, Avishai; Livni, Dorit; Regev, Itai; Segal, Victor; Gover, Dan

2016-05-01

Cryogenic refrigerators represent a significant enabling technology for Earth and Space science enterprises. Many of the space instruments require cryogenic refrigeration to enable the use of advanced detectors to explore a wide range of phenomena from space. RICOR refrigerators involved in various space missions are overviewed in this paper, starting in 1994 with "Clementine" Moon mission, till the latest ExoMars mission launched in 2016. RICOR tactical rotary refrigerators have been incorporated in many space instruments, after passing qualification, life time, thermal management testing and flight acceptance. The tactical to space customization framework includes an extensive characterization and qualification test program to validate reliability, the design of thermal interfacing with a detector, vibration export control, efficient heat dissipation in a vacuum environment, robustness, mounting design, compliance with outgassing requirements and strict performance screening. Current RICOR development is focused on dedicated ultra-long-life, highly reliable, space cryogenic refrigerator based on a Pulse Tube design

Quantum speed limit constraints on a nanoscale autonomous refrigerator

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Chiranjib; Misra, Avijit; Bhattacharya, Samyadeb; Pati, Arun Kumar

2018-06-01

Quantum speed limit, furnishing a lower bound on the required time for the evolution of a quantum system through the state space, imposes an ultimate natural limitation to the dynamics of physical devices. Quantum absorption refrigerators, however, have attracted a great deal of attention in the past few years. In this paper, we discuss the effects of quantum speed limit on the performance of a quantum absorption refrigerator. In particular, we show that there exists a tradeoff relation between the steady cooling rate of the refrigerator and the minimum time taken to reach the steady state. Based on this, we define a figure of merit called "bounding second order cooling rate" and show that this scales linearly with the unitary interaction strength among the constituent qubits. We also study the increase of bounding second-order cooling rate with the thermalization strength. We subsequently demonstrate that coherence in the initial three qubit system can significantly increase the bounding second-order cooling rate. We study the efficiency of the refrigerator at maximum bounding second-order cooling rate and, in a limiting case, we show that the efficiency at maximum bounding second-order cooling rate is given by a simple formula resembling the Curzon-Ahlborn relation.

A Reversible Thermally Driven Pump for Use in a Sub-Kelvin Magnetic Refrigerator

NASA Technical Reports Server (NTRS)

Miller, Franklin K.

2012-01-01

A document describes a continuous magnetic refrigerator that is suited for cooling astrophysics detectors. This refrigerator has the potential to provide efficient, continuous cooling to temperatures below 50 mK for detectors, and has the benefits over existing magnetic coolers of reduced mass because of faster cycle times, the ability to pump the cooled fluid to remote cooling locations away from the magnetic field created by the superconducting magnet, elimination of the added complexity and mass of heat switches, and elimination of the need for a thermal bus and single crystal paramagnetic materials due to the good thermal contact between the fluid and the paramagnetic material. A reliable, thermodynamically efficient pump that will work at 1.8 K was needed to enable development of the new magnetic refrigerator. The pump consists of two canisters packed with pieces of gadolinium gallium garnet (GGG). The canisters are connected by a superleak (a porous piece of VYCOR glass). A superconducting magnetic coil surrounds each of the canisters. The configuration enables driving of cyclic thermodynamic cycles (such as the sub-Kelvin Active Magnetic Regenerative Refrigerator) without using pistons or moving parts.

Experimental study on a prototype of heat pipe solar water heater using refrigerant R134a as a transfer fluid

NASA Astrophysics Data System (ADS)

Sitepu, T.; Sembiring, J.; Ambarita, H.

2018-02-01

A prototype of a solar water heater by using refrigerant as a heat transfer fluid is investigated experimentally. The objective is to explore the characteristics and the performance of the prototype. To make heat transfer from the collector to the heated fluid effectively, refrigerant R134a is used as a transfer. In the experiments, the initial pressure inside the heat pipe is varied. The prototype is exposed to solar irradiation in a location in Medan city for three days of the experiment. Solar collector temperatures, solar radiation, water temperature, and ambient temperature are measured. The efficiency of the system is analyzed. The results show that temperature of the hot water increases as the initial pressure of the working fluid increase. However, the increasing is not linear, and there must exist an optimum initial pressure. For the case with the refrigerant pressure of 110 psi, the maximum hot water temperature and maximum thermal efficiency are 45.36oC and 53.23%, respectively. The main conclusion can be drawn here is that solar water heater by using refrigerant R134a should be operated at initial pressure 110 psi.

Review on Applications of NanoFluids used in Vapour Compression Refrigeration System for Cop Enhancement

NASA Astrophysics Data System (ADS)

Veera Raghavalu, K.; Govindha Rasu, N.

2018-03-01

The present research paper focuses on the use of Nano additive refrigerants in vapor compression refrigeration system (VCRS) because of their amazing development during Thermo Physical along with heat transfer potential to improve the coefficient of performance (COP) and reliability of refrigeration system. Furthermore, challenges and future instructions of performance enhancement of VCRS using Nano additive refrigerants were presented. Lubricant oil is essential in the entire vapour compression refrigeration systems, mostly for the efficient function of the compressor. But, some assign of the oil is entire the cycle oil circulates with the refrigerant. Presently, an assortment of investigation is going on in the field of the Nano-particles like metals, oxides, carbon Nano-tubes or carbides. Nano-lubricants are unique type of Nano-fluids which are varieties of Nano-particles, lubricants and have a wide variety in the fields of refrigeration systems. This paper, has been done on the application of Nano-particles balanced in lubricating oils of refrigerating systems are reviewed. The aim of this investigation is to study and find which type of lubricant oil works better with Nano-particles in the area of refrigeration. From the review of literature, it has been observed that Nano-particles mixed with mineral oil gives enhanced results than polyolester (POE) oil.

Evaluation of Enthalpy Diagrams for NH3-H2O Absorption Refrigerator

NASA Astrophysics Data System (ADS)

Takei, Toshitaka; Saito, Kiyoshi; Kawai, Sunao

The protection of environment is becoming a grave problem nowadays and an absorption refrigerator, which does not use fleon as a refrigerant, is acquiring a close attention. Among the absorption refrigerators, a number of ammonia-water absorption refrigerators are being used in realm such as refrigeration and ice accumulation, since this type of refrigerator can produce below zero degree products. It is essential to conduct an investigation on the characteristics of ammonia-water absorption refrigerator in detail by means of computer simulation in order to realize low cost, highly efficient operation. Unfortunately, there have been number of problems in order to conduct computer simulations. Firstly, Merkel's achievements of enthalpy diagram does not give the relational equations. And secondly, although relational equation are being proposed by Ziegler, simpler equations that can be applied to computer simulation are yet to be proposed. In this research, simper equations based on Ziegler's equations have been derived to make computer simulation concerning the performance of ammonia-water absorption refrigerator possible-Both results of computer simulations using simple equations and Merkel's enthalpy diagram respectively, have been compared with the actual experimental data of one staged ammonia-water absorption refrigerator. Consequently, it is clarified that the results from Ziegler's equations agree with experimental data better than those from Merkel's enthalpy diagram.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sikes, Karen; Blackburn, Julia; Grubbs, Tyler

Despite a steady record of energy efficiency improvements in residential refrigerators and freezers over recent decades, these products still account for 4% of the site energy consumption for the average U.S. household. The Oak Ridge National Laboratory (ORNL) – along with partners Sandia National Laboratories (SNL) and the University of Maryland – are pursuing further efficiency improvements in this market sector by using a novel/prototype rotating heat exchanger (RHX) based on a Sandia Cooler technology as an evaporator in a residential refrigerator-freezer. The purpose of this study is to investigate the market potential of refrigerator-freezer products equipped with RHX evaporatorsmore » in the United States, including projections of maximum annual market share and unit shipments and maximum direct and indirect job creation.« less

Limited options for low-global-warming-potential refrigerants

DOE PAGES

McLinden, Mark O.; Brown, J. Steven; Brignoli, Riccardo; ...

2017-02-17

Hydrofluorocarbons, currently used as refrigerants in air-conditioning systems, are potent greenhouse gases, and their contribution to climate change is projected to increase. Future use of the hydrofluorocarbons will be phased down and, thus replacement fluids must be found. Here we show that only a few pure fluids possess the combination of chemical, environmental, thermodynamic, and safety properties necessary for a refrigerant and that these fluids are at least slightly flammable.We search for replacements by applying screening criteria to a comprehensive chemical database. For the fluids passing the thermodynamic and environmental screens (critical temperature and global warming potential), we simulate performancemore » in small air-conditioning systems, including optimization of the heat exchangers. We show that the efficiency-versus-capacity trade-off that exists in an ideal analysis disappears when a more realistic system is considered. Furthermore, the maximum efficiency occurs at a relatively high volumetric refrigeration capacity, but there are few fluids in this range.« less

Performance comparison of single-stage mixed-refrigerant Joule-Thomson cycle and reverse Brayton cycle for cooling 80 to 120 K temperature-distributed heat loads

NASA Astrophysics Data System (ADS)

Wang, H. C.; Chen, G. F.; Gong, M. Q.; Li, X.

2017-12-01

Thermodynamic performance comparison of single-stage mixed-refrigerant Joule-Thomson cycle (MJTR) and pure refrigerant reverse Brayton cycle (RBC) for cooling 80 to 120 K temperature-distributed heat loads was conducted in this paper. Nitrogen under various liquefaction pressures was employed as the heat load. The research was conducted under nonideal conditions by exergy analysis methods. Exergy efficiency and volumetric cooling capacity are two main evaluation parameters. Exergy loss distribution in each process of refrigeration cycle was also investigated. The exergy efficiency and volumetric cooling capacity of MJTR were obviously superior to RBC in 90 to 120 K temperature zone, but still inferior to RBC at 80 K. The performance degradation of MJTR was caused by two main reasons: The high fraction of neon resulted in large entropy generation and exergy loss in throttling process. Larger duty and WLMTD lead to larger exergy losses in recuperator.

Limited options for low-global-warming-potential refrigerants

DOE Office of Scientific and Technical Information (OSTI.GOV)

McLinden, Mark O.; Brown, J. Steven; Brignoli, Riccardo

Hydrofluorocarbons, currently used as refrigerants in air-conditioning systems, are potent greenhouse gases, and their contribution to climate change is projected to increase. Future use of the hydrofluorocarbons will be phased down and, thus replacement fluids must be found. Here we show that only a few pure fluids possess the combination of chemical, environmental, thermodynamic, and safety properties necessary for a refrigerant and that these fluids are at least slightly flammable.We search for replacements by applying screening criteria to a comprehensive chemical database. For the fluids passing the thermodynamic and environmental screens (critical temperature and global warming potential), we simulate performancemore » in small air-conditioning systems, including optimization of the heat exchangers. We show that the efficiency-versus-capacity trade-off that exists in an ideal analysis disappears when a more realistic system is considered. Furthermore, the maximum efficiency occurs at a relatively high volumetric refrigeration capacity, but there are few fluids in this range.« less

Max Tech Efficiency Electric HPWH with low-GWP Halogenated Refrigerant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nawaz, Kashif; Shen, Bo; Elatar, Ahmed F.

A scoping-level analysis was conducted to determine the maximum performance of an electric heat pump water heater (HPWH) with low GWP refrigerants (hydroflouroolefins (HFO), hydrofluorocarbons (HFC), and blends). A baseline heat pump water heater (GE GeoSpring) deploying R-134a was analyzed first using the DOE/ORNL Heat Pump Design Model (HPDM) modeling tool. The model was calibrated using experimental data to match the water temperature stratification in tank, first hour rating, energy factor and coefficient of performance. A CFD modeling tool was used to further refine the HPDM tank model. After calibration, the model was used to simulate the performance of alternativemore » refrigerants. The parametric analysis concluded that by appropriate selection of equipment size and condenser tube wrap configuration the overall performance of emerging low GWP refrigerants for HPWH application not only exceed the Energy Star Energy Factor criteria i.e. 2.20, but is also comparable to some of the most efficient products in the market.« less

Efficient super-resolution image reconstruction applied to surveillance video captured by small unmanned aircraft systems

NASA Astrophysics Data System (ADS)

He, Qiang; Schultz, Richard R.; Chu, Chee-Hung Henry

2008-04-01

The concept surrounding super-resolution image reconstruction is to recover a highly-resolved image from a series of low-resolution images via between-frame subpixel image registration. In this paper, we propose a novel and efficient super-resolution algorithm, and then apply it to the reconstruction of real video data captured by a small Unmanned Aircraft System (UAS). Small UAS aircraft generally have a wingspan of less than four meters, so that these vehicles and their payloads can be buffeted by even light winds, resulting in potentially unstable video. This algorithm is based on a coarse-to-fine strategy, in which a coarsely super-resolved image sequence is first built from the original video data by image registration and bi-cubic interpolation between a fixed reference frame and every additional frame. It is well known that the median filter is robust to outliers. If we calculate pixel-wise medians in the coarsely super-resolved image sequence, we can restore a refined super-resolved image. The primary advantage is that this is a noniterative algorithm, unlike traditional approaches based on highly-computational iterative algorithms. Experimental results show that our coarse-to-fine super-resolution algorithm is not only robust, but also very efficient. In comparison with five well-known super-resolution algorithms, namely the robust super-resolution algorithm, bi-cubic interpolation, projection onto convex sets (POCS), the Papoulis-Gerchberg algorithm, and the iterated back projection algorithm, our proposed algorithm gives both strong efficiency and robustness, as well as good visual performance. This is particularly useful for the application of super-resolution to UAS surveillance video, where real-time processing is highly desired.

A new boil-off gas re-liquefaction system for LNG carriers based on dual mixed refrigerant cycle

NASA Astrophysics Data System (ADS)

Tan, Hongbo; Shan, Siyu; Nie, Yang; Zhao, Qingxuan

2018-06-01

A new boil-off gas (BOG) re-liquefaction system for LNG carriers has been proposed to improve the system energy efficiency. Two cascade mixed refrigerant cycles (or dual mixed refrigerant cycle, DMR) are used to provide the cooling capacity for the re-liquefaction of BOG. The performance of the new system is analysed on the basis of the thermodynamic data obtained in the process simulation in Aspen HYSYS software. The results show that the power consumed in the BOG compressor and the high-temperature mixed refrigerant compressor could be saved greatly due to the reduced mass flow rates of the processed fluids. Assuming the re-liquefaction capacity of the investigated system is 4557.6 kg/h, it is found that the total power consumption can be reduced by 25%, from 3444 kW in the existing system to 2585.8 kW in the proposed system. The coefficient of performance (COP) of 0.25, exergy efficiency of 41.3% and the specific energy consumption (SEC) of 0.589 kWh/kg(LNG) could be achieved in the new system. It exhibits 33% of improvement in the COP and exergy efficiency in comparison with the corresponding values of the existing system. It indicates that employing the DMR based BOG re-liquefaction system could improve the system energy efficiency of LNG carriers substantially.

Estimates of Refrigerator Loads in Public Housing Based on Metered Consumption Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, JD; Pratt, RG

1998-09-11

The New York Power Authority (NYPA), the New York City Housing Authority (NYCHA), and the U.S. Departments of Housing and Urban Development (HUD) and Energy (DOE) have joined in a project to replace refrigerators in New York City public housing with new, highly energy-efficient models. This project laid the ground work for the Consortium for Energy Efficiency (CEE) and DOE to enable housing authorities throughout the United States to bulk-purchase energy-efficient appliances. DOE helped develop and plan the program through the ENERGY STAR@ Partnerships program conducted by its Pacific Nofiwest National Laboratory (PNNL). PNNL was subsequently asked to conduct themore » savings evahations for 1996 and 1997. PNNL designed the metering protocol and occupant survey, supplied and calibrated the metering equipment, and managed and analyzed the data. The 1996 metering study of refrigerator energy usage in New York City public housing (Pratt and Miller 1997) established the need and justification for a regression-model-based approach to an energy savings estimate. The need originated in logistical difficulties associated with sampling the population and pen?orming a stratified analysis. Commonly, refrigerators[a) with high representation in the population were missed in the sampling schedule, leaving significant holes in the sample and difficulties for the stratified anrdysis. The just{jfcation was found in the fact that strata (distinct groups of identical refrigerators) were not statistically distinct in terms of their label ratio (ratio of metered consumption to label rating). This finding suggested a general regression model could be used to represent the consumption of all refrigerators in the population. In 1996 a simple two-coefficient regression model, a function of only the refrigerator label rating, was developed and used to represent the existing population of refrigerators. A key concept used in the 1997 study grew from findings in a small number of apartments metered in 1996 with a detailed protocol. Fifteen-minute time-series data of ambient and compartment temperatures and refrigerator power were analyzed and demonstrated the potential for reducing power records into three components. This motivated the development of an analysis process to divide the metered consumption into baseline load, occupant-associated load, and defrosting load. The baseline load is the consumption that would occur if the refrigerator were on but had no occupant usage load (no door-opening events) and the defrosting mechanism was disabled. The motivation behind this component reduction process was the hope that components could be more effectively modeled than the total. We reasoned that the components would lead to abetter (more general and more significant) understanding of the relationships between consumption, the characteristics of the refrigerator, and its operating environment.« less

Air Conditioning with Magnetic Refrigeration : An Efficient, Green Compact Cooling System Using Magnetic Refrigeration

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-09-01

BEETIT Project: Astronautics is developing an air conditioning system that relies on magnetic fields. Typical air conditioners use vapor compression to cool air. Vapor compression uses a liquid refrigerant to circulate within the air conditioner, absorb the heat, and pump the heat out into the external environment. Astronautics’ design uses a novel property of certain materials, called “magnetocaloric materials”, to achieve the same result as liquid refrigerants. These magnetocaloric materials essentially heat up when placed within a magnetic field and cool down when removed, effectively pumping heat out from a cooler to warmer environment. In addition, magnetic refrigeration uses nomore » ozone-depleting gases and is safer to use than conventional air conditioners which are prone to leaks.« less

Investigation of Energy-Efficient Supermarket Display Cases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walker, D.H.

Supermarkets represent one of the largest energy-intensive building groups in the commercial sector, consuming 2 to 3 million kWh/yr per store (ES-1). Over half of this energy use is for the refrigeration of food display cases and storage coolers. Display cases are used throughout a supermarket for the merchandising of perishable food products. The cases are maintained at air temperatures ranging from -10 to 35 F, depending upon the type of product stored. The operating characteristics and energy requirements of the refrigeration system are directly related to the refrigeration load. The sources of the display case refrigeration load consist of:more » (1) Moist and warm air infiltration through the open front of the case--air curtains are employed to inhibit this infiltration, but some ambient air is entrained, which adds a substantial portion to the refrigeration load. (2) Heat conduction through case panels and walls. (3) Thermal radiation from the ambient to the product and display case interior. (4) Internal thermal loads--the use of lights, evaporator fans, periodic defrosts, and antisweat heaters adds to the refrigeration load of the display case as well as directly consuming electric energy. The impact of each of these elements on the refrigeration load is very dependent upon case type (Figure ES-1). For example, air infiltration is the most significant portion of the refrigeration load for open, multi-deck cases, while radiation is the largest part of the load for tub-type cases. The door anti-sweat heaters represent a major share of the refrigeration load for frozen food door reach-in cases. Figure ES-2 shows the distribution of display cases in a typical supermarket (ES-2). Open, multi-deck, medium temperature display cases typically comprise about half of the refrigerated fixtures in a store (ES-3). In addition, medium temperature fixtures and storage coolers account for roughly 70 to 75 percent of the total store refrigeration load with open, multi-deck cases contributing about 3/4 of that fraction. Consequently, the focus of this investigation has tilted toward the open, vertical, multi-deck medium temperature case type. Various technologies and control methods are energy efficiency measures (EEMs) that could be applied to display cases and result in the reduction of the refrigeration load and of the energy consumption of the supermarket refrigeration system. An extensive evaluation of the EEMs was conducted in order to select those that met the following criteria: (1) Near-term implementation--All EEMs considered could be implemented with existing refrigeration hardware and technology. (2) Potential for energy-efficiency improvements--Energy savings and/or refrigeration load reduction must be obtained by the implementation of the EEM. (3) Enhancement of the ability to maintain target product temperature--Proper operation of the display case and maintenance of the stored product temperature could not be compromised by the use of the EEM. The energy impact of a number of viable display case EEMs was quantified by performing whole building hourly simulations. A special version of the U.S. Department of Energy's (DOE-2.3) program was used to develop a model of a supermarket. The model was then calibrated using available end-use monitored data to increase confidence in simulation results.« less

76 FR 17573 - Energy Conservation Standards for Commercial Refrigeration Equipment: Public Meeting and...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-30

... Preliminary Technical Support Document AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy. ACTION: Notice of public meeting and availability of preliminary technical support document... refrigeration equipment. In addition, DOE encourages written comments on these subjects. To inform interested...

Physical control oriented model of large scale refrigerators to synthesize advanced control schemes. Design, validation, and first control results

NASA Astrophysics Data System (ADS)

Bonne, François; Alamir, Mazen; Bonnay, Patrick

2014-01-01

In this paper, a physical method to obtain control-oriented dynamical models of large scale cryogenic refrigerators is proposed, in order to synthesize model-based advanced control schemes. These schemes aim to replace classical user experience designed approaches usually based on many independent PI controllers. This is particularly useful in the case where cryoplants are submitted to large pulsed thermal loads, expected to take place in the cryogenic cooling systems of future fusion reactors such as the International Thermonuclear Experimental Reactor (ITER) or the Japan Torus-60 Super Advanced Fusion Experiment (JT-60SA). Advanced control schemes lead to a better perturbation immunity and rejection, to offer a safer utilization of cryoplants. The paper gives details on how basic components used in the field of large scale helium refrigeration (especially those present on the 400W @1.8K helium test facility at CEA-Grenoble) are modeled and assembled to obtain the complete dynamic description of controllable subsystems of the refrigerator (controllable subsystems are namely the Joule-Thompson Cycle, the Brayton Cycle, the Liquid Nitrogen Precooling Unit and the Warm Compression Station). The complete 400W @1.8K (in the 400W @4.4K configuration) helium test facility model is then validated against experimental data and the optimal control of both the Joule-Thompson valve and the turbine valve is proposed, to stabilize the plant under highly variable thermals loads. This work is partially supported through the European Fusion Development Agreement (EFDA) Goal Oriented Training Program, task agreement WP10-GOT-GIRO.

Physical control oriented model of large scale refrigerators to synthesize advanced control schemes. Design, validation, and first control results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonne, François; Bonnay, Patrick; Alamir, Mazen

2014-01-29

In this paper, a physical method to obtain control-oriented dynamical models of large scale cryogenic refrigerators is proposed, in order to synthesize model-based advanced control schemes. These schemes aim to replace classical user experience designed approaches usually based on many independent PI controllers. This is particularly useful in the case where cryoplants are submitted to large pulsed thermal loads, expected to take place in the cryogenic cooling systems of future fusion reactors such as the International Thermonuclear Experimental Reactor (ITER) or the Japan Torus-60 Super Advanced Fusion Experiment (JT-60SA). Advanced control schemes lead to a better perturbation immunity and rejection,more » to offer a safer utilization of cryoplants. The paper gives details on how basic components used in the field of large scale helium refrigeration (especially those present on the 400W @1.8K helium test facility at CEA-Grenoble) are modeled and assembled to obtain the complete dynamic description of controllable subsystems of the refrigerator (controllable subsystems are namely the Joule-Thompson Cycle, the Brayton Cycle, the Liquid Nitrogen Precooling Unit and the Warm Compression Station). The complete 400W @1.8K (in the 400W @4.4K configuration) helium test facility model is then validated against experimental data and the optimal control of both the Joule-Thompson valve and the turbine valve is proposed, to stabilize the plant under highly variable thermals loads. This work is partially supported through the European Fusion Development Agreement (EFDA) Goal Oriented Training Program, task agreement WP10-GOT-GIRO.« less

Model-based optimizations of packaged rooftop air conditioners using low global warming potential refrigerants

DOE PAGES

Shen, Bo; Abdelaziz, Omar; Shrestha, Som; ...

2017-10-31

Based on laboratory investigations for R-22 and R-410A alternative low GWP refrigerants in two baseline rooftop air conditioners (RTU), the DOE/ORNL Heat Pump Design Model was used to model the two RTUs and the models were calibrated against the experimental data. We compared the compressor efficiencies and heat exchanger performances. An efficiency-based compressor mapping method was developed. Extensive model-based optimizations were conducted to provide a fair comparison between all the low GWP candidates by selecting optimal configurations. The results illustrate that all the R-22 low GWP refrigerants will lead to slightly lower COPs. ARM-20B appears to be the best R-22more » replacement at normal conditions. At higher ambient temperatures, ARM-20A exhibits better performance. All R-410A low GWP candidates will result in similar or better efficiencies than R-410A. R-32 has the best COP while requiring the smallest compressor. Finally, R-452B uses the closest compressor displacement volume and achieves the same efficiency as R-410A.« less

Model-based optimizations of packaged rooftop air conditioners using low global warming potential refrigerants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Bo; Abdelaziz, Omar; Shrestha, Som

Based on laboratory investigations for R-22 and R-410A alternative low GWP refrigerants in two baseline rooftop air conditioners (RTU), the DOE/ORNL Heat Pump Design Model was used to model the two RTUs and the models were calibrated against the experimental data. We compared the compressor efficiencies and heat exchanger performances. An efficiency-based compressor mapping method was developed. Extensive model-based optimizations were conducted to provide a fair comparison between all the low GWP candidates by selecting optimal configurations. The results illustrate that all the R-22 low GWP refrigerants will lead to slightly lower COPs. ARM-20B appears to be the best R-22more » replacement at normal conditions. At higher ambient temperatures, ARM-20A exhibits better performance. All R-410A low GWP candidates will result in similar or better efficiencies than R-410A. R-32 has the best COP while requiring the smallest compressor. Finally, R-452B uses the closest compressor displacement volume and achieves the same efficiency as R-410A.« less

Design of high-efficiency Joule-Thomson cycles for high-temperature superconductor power cable cooling

NASA Astrophysics Data System (ADS)

Jin, Lingxue; Lee, Cheonkyu; Baek, Seungwhan; Jeong, Sangkwon

2018-07-01

Liquid nitrogen (LN2) is commonly used as the coolant of a high temperature superconductor (HTS) power cable. The LN2 is continuously cooled by a subcooler to maintain an appropriate operating temperature of the cable. This paper proposes two Joule-Thomson (JT) refrigeration cycles for subcooling the LN2 coolant by using nitrogen itself as the working fluid. Additionally, an innovative HTS cooling cycle, of which the cable coolant and the refrigerant are unified and supplied from the same source, is suggested and analyzed in detail. Among these cycles, the highest COP is obtained in the JT cycle with a vacuum pump (Cycle A) which is 0.115 at 78 K, and the Carnot efficiency is 32.8%. The integrated HTS cooling cycle (Cycle C) can reach the maximum COP of 0.087, and the Carnot efficiency of 24.8%. Although Cycle C has a relatively low cycle efficiency when compared to that of the separated refrigeration cycle, it can be a good alternative in engineering applications, because the assembled hardware has few machinery components in a more compact configuration than the other cycles.

10 CFR 431.292 - Definitions concerning refrigerated bottled or canned beverage vending machines.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., and functional (or hydraulic) characteristics that affect energy consumption, energy efficiency, water... 10 Energy 3 2012-01-01 2012-01-01 false Definitions concerning refrigerated bottled or canned beverage vending machines. 431.292 Section 431.292 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY...

10 CFR 431.292 - Definitions concerning refrigerated bottled or canned beverage vending machines.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., and functional (or hydraulic) characteristics that affect energy consumption, energy efficiency, water... 10 Energy 3 2013-01-01 2013-01-01 false Definitions concerning refrigerated bottled or canned beverage vending machines. 431.292 Section 431.292 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY...

10 CFR 431.292 - Definitions concerning refrigerated bottled or canned beverage vending machines.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., and functional (or hydraulic) characteristics that affect energy consumption, energy efficiency, water... 10 Energy 3 2014-01-01 2014-01-01 false Definitions concerning refrigerated bottled or canned beverage vending machines. 431.292 Section 431.292 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY...

EPA'S RESEARCH PROJECTS RELATING TO THE DUAL-CIRCUIT AND LORENZ REFRIGERATOR/FREEZERS

EPA Science Inventory

The paper discusses EPA research projects relating to the dual-circuit and Lorenz refrigerator/freezers (RFs). EPA is interested in not only phasing out chlorofluorocarbons (CFCs) in RFs, but doing so in a way that will maximize energy efficiency and minimize subsequent impacts o...

Correlation of refrigerant mass flow rate through adiabatic capillary tubes using mixture refrigerant carbondioxide and ethane for low temperature applications

NASA Astrophysics Data System (ADS)

Nasruddin, Syaka, Darwin R. B.; Alhamid, M. Idrus

2012-06-01

Various binary mixtures of carbon dioxide and hydrocarbons, especially propane or ethane, as alternative natural refrigerants to Chlorofluorocarbons (CFCs) or Hydro fluorocarbons (HFCs) are presented in this paper. Their environmental performance is friendly, with an ozone depletion potential (ODP) of zero and Global-warming potential (GWP) smaller than 20. The capillary tube performance for the alternative refrigerant HFC HCand mixed refrigerants have been widely studied. However, studies that discuss the performance of the capillary tube to a mixture of natural refrigerants, in particular a mixture of azeotrope carbon dioxide and ethane is still undeveloped. A method of empirical correlation to determine the mass flow rate and pipe length has an important role in the design of the capillary tube for industrial refrigeration. Based on the variables that effect the rate of mass flow of refrigerant in the capillary tube, the Buckingham Pi theorem formulated eight non-dimensional parameters to be developed into an empirical equations correlation. Furthermore, non-linear regression analysis used to determine the co-efficiency and exponent of this empirical correlation based on experimental verification of the results database.

Influence of other rare earth ions on the optical refrigeration efficiency in Yb:YLF crystals.

PubMed

Di Lieto, Alberto; Sottile, Alberto; Volpi, Azzurra; Zhang, Zhonghan; Seletskiy, Denis V; Tonelli, Mauro

2014-11-17

We investigated the effect of rare earth impurities on the cooling efficiency of Yb³⁺:LiYF₄ (Yb:YLF). The refrigeration performance of two single crystals, doped with 5%-at. Yb and with identical history but with different amount of contaminations, have been compared by measuring the cooling efficiency curves. Spectroscopic and elemental analyses of the samples have been carried out to identify the contaminants, to quantify their concentrations and to understand their effect on the cooling efficiencies. A model of energy transfer processes between Yb and other rare earth ions is suggested, identifying Erbium and Holmium as elements that produce a detrimental effect on the cooling performance.

Thermodynamic design of 10 kW Brayton cryocooler for HTS cable

NASA Astrophysics Data System (ADS)

Chang, Ho-Myung; Park, C. W.; Yang, H. S.; Sohn, Song Ho; Lim, Ji Hyun; Oh, S. R.; Hwang, Si Dole

2012-06-01

Thermodynamic design of Brayton cryocooler is presented as part of an ongoing governmental project in Korea, aiming at 1 km HTS power cable in the transmission grid. The refrigeration requirement is 10 kW for continuously sub-cooling liquid nitrogen from 72 K to 65 K. An ideal Brayton cycle for this application is first investigated to examine the fundamental features. Then a practical cycle for a Brayton cryocooler is designed, taking into account the performance of compressor, expander, and heat exchangers. Commercial software (Aspen HYSYS) is used for simulating the refrigeration cycle with real fluid properties of refrigerant. Helium is selected as a refrigerant, as it is superior to neon in thermodynamic efficiency. The operating pressure and flow rate of refrigerant are decided with a constraint to avoid the freezing of liquid nitrogen

Review of vortex tube expansion in vapour compression refrigeration system

NASA Astrophysics Data System (ADS)

Liu, Yefeng; Yu, Jun

2018-05-01

A vortex tube expansion device replacing the throttle valve is proposed to improve the efficiency of vapour compression refrigeration cycle by reducing the loss of irreversibility in expansion process. The vortex tube is well-suited for these applications because it is simple, compact, light, quiet. Thus, this paper presents an overview of the thermodynamic analysis of vapour compression refrigeration cycle with vortex tube expansion device using different refrigerants. The paper also reviews the experiments and the calculations presented in previous studies on temperature separation in the vortex tube. The temperature separation mechanism and the flow-field inside the vortex tubes is explored by measuring the pressure, velocity, and temperature fields.

Design optimization of single mixed refrigerant LNG process using a hybrid modified coordinate descent algorithm

NASA Astrophysics Data System (ADS)

Qyyum, Muhammad Abdul; Long, Nguyen Van Duc; Minh, Le Quang; Lee, Moonyong

2018-01-01

Design optimization of the single mixed refrigerant (SMR) natural gas liquefaction (LNG) process involves highly non-linear interactions between decision variables, constraints, and the objective function. These non-linear interactions lead to an irreversibility, which deteriorates the energy efficiency of the LNG process. In this study, a simple and highly efficient hybrid modified coordinate descent (HMCD) algorithm was proposed to cope with the optimization of the natural gas liquefaction process. The single mixed refrigerant process was modeled in Aspen Hysys® and then connected to a Microsoft Visual Studio environment. The proposed optimization algorithm provided an improved result compared to the other existing methodologies to find the optimal condition of the complex mixed refrigerant natural gas liquefaction process. By applying the proposed optimization algorithm, the SMR process can be designed with the 0.2555 kW specific compression power which is equivalent to 44.3% energy saving as compared to the base case. Furthermore, in terms of coefficient of performance (COP), it can be enhanced up to 34.7% as compared to the base case. The proposed optimization algorithm provides a deep understanding of the optimization of the liquefaction process in both technical and numerical perspectives. In addition, the HMCD algorithm can be employed to any mixed refrigerant based liquefaction process in the natural gas industry.

Evaluation and analysis on the coupling performance of a high-speed turboexpander compressor

NASA Astrophysics Data System (ADS)

Chen, Shuangtao; Fan, Yufeng; Yang, Shanju; Chen, Xingya; Hou, Yu

2017-12-01

A high-speed turboexpander compressor (TEC) for small reverse Brayton air refrigerator is tested and analyzed in the present work. A TEC consists of an expander and a compressor, which are coupled together and interact with each other directly. Meanwhile, the expander and compressor have different effects on the refrigerator. The TEC overall efficiency, which contains effects of the expander's expansion, the compressor's pre-compression, and the pressure drop between them, was proved. It unifies influences of both compression and expansion processes on the COP of refrigerator and could be used to evaluate the TEC overall performance. Then, the coupling parameters were analyzed, which shows that for a TEC, the expander efficiency should be fully utilized first, followed by the compressor pressure ratio. Experiments were carried out to test the TEC coupling performances. The results indicated that, the TEC overall efficiency could reach 67.2%, and meanwhile 22.3% of the energy output was recycled.

A small, single stage orifice pulse tube cryocooler demonstration

NASA Technical Reports Server (NTRS)

Hendricks, John B.

1990-01-01

This final report summarizes and presents the analytical and experimental progress in the present effort. The principal objective of this effort was the demonstration of a 0.25 Watt, 80 Kelvin orifice pulse tube refrigerator. The experimental apparatus is described. The design of a partially optimized pulse tube refrigerator is included. The refrigerator demonstrates an ultimate temperature of 77 K, has a projected cooling power of 0.18 Watts at 80 K, and has a measured cooling power of 1 Watt at 97 K, with an electrical efficiency of 250 Watts/Watt, much better than previous pulse tube refrigerators. A model of the pulse tube refrigerator that provides estimates of pressure ratio and mass flow within the pulse tube refrigerator, based on component physical characteristics is included. A model of a pulse tube operation based on generalized analysis which is adequate to support local optimization of existing designs is included. A model of regenerator performance based on an analogy to counterflow heat exchangers is included.

Mixed refrigerant cycle with neon, hydrogen, and helium for cooling sc power transmission lines

NASA Astrophysics Data System (ADS)

Kloeppel, S.; Dittmar, N.; Haberstroh, Ch; Quack, H.

2017-02-01

The use of superconductors in very long power transmission lines requires a reliable and effective cooling. Since the use of cryocoolers does not appear feasible for very long distances, a cryogenic refrigeration cycle needs to be developed. For cooling superconducting cables based on MgB2 (T c = 39 K), liquid hydrogen (LH2) is the obvious cooling agent. For recooling LH2, one would need a refrigeration cycle providing temperatures at around 20 K. For this purpose, one could propose the use of a helium refrigeration cycle. But the very low molecular weight of helium restricts the use of turbo compressors, which limits the overall efficiency. In order to increase the molecular weight of the refrigerant a mixture of cryogens could be used, allowing the use of a turbo compressor. Temperatures below the triple point of neon are achieved by phase separation. This paper presents a possible layout of a refrigeration cycle utilizing a three component mixture of neon, hydrogen, and helium.

Magnetic cooling for microkelvin nanoelectronics on a cryofree platform.

PubMed

Palma, M; Maradan, D; Casparis, L; Liu, T-M; Froning, F N M; Zumbühl, D M

2017-04-01

We present a parallel network of 16 demagnetization refrigerators mounted on a cryofree dilution refrigerator aimed to cool nanoelectronic devices to sub-millikelvin temperatures. To measure the refrigerator temperature, the thermal motion of electrons in a Ag wire-thermalized by a spot-weld to one of the Cu nuclear refrigerators-is inductively picked-up by a superconducting gradiometer and amplified by a SQUID mounted at 4 K. The noise thermometer as well as other thermometers are used to characterize the performance of the system, finding magnetic field independent heat-leaks of a few nW/mol, cold times of several days below 1 mK, and a lowest temperature of 150 μK of one of the nuclear stages in a final field of 80 mT, close to the intrinsic SQUID noise of about 100 μK. A simple thermal model of the system capturing the nuclear refrigerator, heat leaks, and thermal and Korringa links describes the main features very well, including rather high refrigerator efficiencies typically above 80%.

Cooling system for superconducting magnet

DOEpatents

Gamble, Bruce B.; Sidi-Yekhlef, Ahmed

1998-01-01

A cooling system is configured to control the flow of a refrigerant by controlling the rate at which the refrigerant is heated, thereby providing an efficient and reliable approach to cooling a load (e.g., magnets, rotors). The cooling system includes a conduit circuit connected to the load and within which a refrigerant circulates; a heat exchanger, connected within the conduit circuit and disposed remotely from the load; a first and a second reservoir, each connected within the conduit, each holding at least a portion of the refrigerant; a heater configured to independently heat the first and second reservoirs. In a first mode, the heater heats the first reservoir, thereby causing the refrigerant to flow from the first reservoir through the load and heat exchanger, via the conduit circuit and into the second reservoir. In a second mode, the heater heats the second reservoir to cause the refrigerant to flow from the second reservoir through the load and heat exchanger via the conduit circuit and into the first reservoir.

Cooling system for superconducting magnet

DOEpatents

Gamble, B.B.; Sidi-Yekhlef, A.

1998-12-15

A cooling system is configured to control the flow of a refrigerant by controlling the rate at which the refrigerant is heated, thereby providing an efficient and reliable approach to cooling a load (e.g., magnets, rotors). The cooling system includes a conduit circuit connected to the load and within which a refrigerant circulates; a heat exchanger, connected within the conduit circuit and disposed remotely from the load; a first and a second reservoir, each connected within the conduit, each holding at least a portion of the refrigerant; a heater configured to independently heat the first and second reservoirs. In a first mode, the heater heats the first reservoir, thereby causing the refrigerant to flow from the first reservoir through the load and heat exchanger, via the conduit circuit and into the second reservoir. In a second mode, the heater heats the second reservoir to cause the refrigerant to flow from the second reservoir through the load and heat exchanger via the conduit circuit and into the first reservoir. 3 figs.

Modifications to JLab 12 GeV Refrigerator and Wide Range Mix Mode Performance Testing Results

NASA Astrophysics Data System (ADS)

Knudsen, P.; Ganni, V.; Hasan, N.; Dixon, K.; Norton, R.; Creel, J.

2017-02-01

Analysis of data obtained during the spring 2013 commissioning of the new 4.5 K refrigeration system at Jefferson Lab (JLab) for the 12 GeV upgrade indicated a wide capacity range with good efficiency and minimal operator interaction. Testing also showed that the refrigerator required higher liquid nitrogen (LN) consumption for its pre-cooler than anticipated by the design. This does not affect the capacity of the refrigerator, but it does result in an increased LN utility cost. During the summer of 2015 the modifications were implemented by the cold box manufacturer, according to a design similar to the JLab 12 GeV cold box specification. Subsequently, JLab recommissioned the cold box and performed extensive performance testing, ranging from 20% to 100% of the design maximum capacity, and in various modes of operation, ranging from pure refrigeration, pure liquefaction, half-and-half mix mode and at selected design modes using the Floating Pressure - Ganni Cycle. The testing demonstrated that the refrigerator system has a good and fairly constant performance over a wide capacity range and different modes of operation. It also demonstrated the modifications resulted in a LN consumption that met the design for the pure refrigeration mode (which is the most demanding) and was lower than the design for the nominal and maximum capacity modes. In addition, a pulsed-load test, similar to what is expected for cryogenic systems supporting fusion experiments, was conducted to observe the response using the Floating Pressure - Ganni Cycle, which was stable and robust. This paper will discuss the results and analysis of this testing pertaining to the LN consumption, the system efficiency over a wide range of capacity and different modes and the behaviour of the system to a pulsed load.

Efficiencies and coefficients of performance of heat engines, refrigerators, and heat pumps with friction: a universal limiting behavior.

PubMed

Bizarro, João P S; Rodrigues, Paulo

2012-11-01

For work-producing heat engines, or work-consuming refrigerators and heat pumps, the percentage decrease caused by friction in their efficiencies, or coefficients of performance (COP's), is approximately given by the ratio W(fric)/W between the work spent against friction forces and the work performed by, or delivered to, the working fluid. This universal scaling, which applies in the limit of small friction (W(fric)/W

Robust video super-resolution with registration efficiency adaptation

NASA Astrophysics Data System (ADS)

Zhang, Xinfeng; Xiong, Ruiqin; Ma, Siwei; Zhang, Li; Gao, Wen

2010-07-01

Super-Resolution (SR) is a technique to construct a high-resolution (HR) frame by fusing a group of low-resolution (LR) frames describing the same scene. The effectiveness of the conventional super-resolution techniques, when applied on video sequences, strongly relies on the efficiency of motion alignment achieved by image registration. Unfortunately, such efficiency is limited by the motion complexity in the video and the capability of adopted motion model. In image regions with severe registration errors, annoying artifacts usually appear in the produced super-resolution video. This paper proposes a robust video super-resolution technique that adapts itself to the spatially-varying registration efficiency. The reliability of each reference pixel is measured by the corresponding registration error and incorporated into the optimization objective function of SR reconstruction. This makes the SR reconstruction highly immune to the registration errors, as outliers with higher registration errors are assigned lower weights in the objective function. In particular, we carefully design a mechanism to assign weights according to registration errors. The proposed superresolution scheme has been tested with various video sequences and experimental results clearly demonstrate the effectiveness of the proposed method.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Bo; Abdelaziz, Omar; Shrestha, Som S.

Based on the laboratory investigation in FY16, for R-22 and R-410A alternative low GWP refrigerants in two baseline rooftop air conditioners (RTU), we used the DOE/ORNL Heat Pump Design Model to model the two RTUs and calibrated the models against the experimental data. Using the calibrated equipment models, we compared the compressor efficiencies, heat exchanger performances. An efficiency-based compressor mapping method was developed, which is able to predict compressor performances of the alternative low GWP refrigerants accurately. Extensive model-based optimizations were conducted to provide a fair comparison between all the low GWP candidates by selecting their preferred configurations at themore » same cooling capacity and compressor efficiencies.« less

75 FR 78809 - Energy Conservation Program for Consumer Products: Test Procedures for Refrigerators...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-16

... reasonably designed to produce test results which measure energy efficiency, energy use * * * or estimated... with at least one of the compartments designed for the refrigerated storage of food and designed to be... with at least one of the compartments designed for the freezing and storage of food at temperatures...

75 FR 29823 - Energy Conservation Program for Consumer Products: Test Procedures for Refrigerators...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-27

...'') sets forth a variety of provisions designed to improve energy efficiency. (All references to EPCA refer... amended under this section shall be reasonably designed to produce test results which measure energy... a cabinet designed for the refrigerated storage of food at temperatures above 32 [deg]F and below 39...

Experimental investigation on the miniature mixed refrigerant cooler driven by a mini-compressor

NASA Astrophysics Data System (ADS)

Chen, Gaofei; Gong, Maoqiong; Wu, Yinong

2018-05-01

Three miniature Joule-Thomson cryogenic coolers and a testing set up were built to investigate the cooling performance in this work. Shell-and-tube heat exchanger and plate fin heat exchangers with rectangular micro channels were designed to achieve high specific surface area. The main processing technology of micro mixed refrigerant cooler (MMRC) was described. The design and fabrication processing of the plate fin heat exchangers were also described. The new developed micro plate-fin type heat exchanger shows high compactness with the specific heat surface larger than 1.0x104 m2/m3. The results of experimental investigations on miniature mixed refrigerant J-T cryogenic coolers driven by a Mini-Compressor were discussed. The performance evaluation and comparison of the three coolers was made to find out the features for each type of cooler. Expressions of refrigeration coefficient and exergy efficiency were pointed out. No-load temperature of about 112 K, and the cooling power of 4.0W at 118K with the input power of 120W is achieved. The exergy efficiency of the SJTC is 5.14%.

R744 ejector technology future perspectives

NASA Astrophysics Data System (ADS)

Hafner, Armin; Banasiak, Krzysztof

2016-09-01

Carbon Dioxide, CO2 (R744) was one of the first commonly applied working fluids in the infancy of refrigeration more than 100 years ago. In contrast to ammonia it mainly disappeared after the first generation of synthetic refrigerants have been introduced to the market after 1930. One reason was that the transition from low-rpm belt driven compressors towards the direct electrical motor driven compressors (50-60 Hz) was not performed for CO2 compressors before the revival introduced by Gustav Lorentzen in the 90is of last century. Since 1988 an enormous R & D effort has been made to further develop CO2 refrigeration technology in spite of the opposition from the chemical industry. Today CO2 refrigeration and heat pumping technologies are accepted as viable and sustainable alternatives for several applications like commercial refrigeration, transport refrigeration, vehicle air conditioning & heat pumping, domestic hot water heat pumps and industrial applications. For some applications, the current threshold to introduce R744 technology can be overcome when the system design takes into account the advantage of the thermo dynamical- and fluid properties of CO2. I.e. the system is designed for transcritical operation with all it pros and cons and takes into consideration how to minimize the losses, and to apply the normally lost expansion work. Shortcut-designs, i.e. drop in solutions, just replacing the H(C)FC refrigeration unit with an CO2 systems adapted for higher system pressures will not result in energy efficient products. CO2 systems do offer the advantage of enabling flooded evaporators supported with adapted ejector technology. These units offer high system performances at low temperature differences and show low temperature air mal-distributions across evaporators. This work gives an overview for the development possibilities for several applications during the next years. Resulting in a further market share increase of CO2 refrigeration and heat pump systems, as energy efficient alternatives to current systems not applying natural working fluids.

Theory and tests of two-phase turbines

NASA Technical Reports Server (NTRS)

Elliott, D. G.

1982-01-01

A theoretical model for two-phase turbines was developed. Apparatus was constructed for testing one- and two-stage turbines (using speed decrease from stage to stage). Turbines were tested with water and nitrogen mixtures and refrigerant 22. Nozzle efficiencies were 0.78 (measured) and 0.72 (theoretical) for water and nitrogen mixtures at a water/nitrogen mixture ratio of 68, by mass; and 0.89 (measured) and 0.84 (theoretical) for refrigerant 22 expanding from 0.02 quality to 0.28 quality. Blade efficiencies (shaft power before windage and bearing loss divided by nozzle jet power) were 0.63 (measured) and 0.71 (theoretical) for water and nitrogen mixtures and 0.62 (measured) and 0.63 (theoretical) for refrigerant 22 with a single stage turbine, and 0,70 (measured) and 0.85 (theoretical) for water and nitrogen mixtures with a two-stage turbine.

Keeping Your Compressor Healthy: Developing the Right Lubricant Formulation is the Key

NASA Astrophysics Data System (ADS)

Karnaz, Joseph A.; Kultgen, Derek W.

2015-08-01

Selecting the correct compressor lubricant is crucial to the duration of the compressor and the refrigerant systems’ useful life. However, developing an optimized lubricant for a refrigeration system requires a multitude of screenings and tests. The compatibility and stability of the lubricant with the refrigerant and compressor components needs to be examined at various accelerated conditions. The lubricant and refrigerant working viscosity must be determined at various refrigerant concentrations, temperatures and pressures as the diluted refrigerant in the lubricant has a significant effect on the viscosity. The correct lubricant formulation needs to be investigated for optimal performance. A compressor lubricant can provide many benefits to a refrigeration system such as bearing durability, sealing, and increased efficiency. Sometimes it is necessary to formulate the lubricant in order to optimize system performance. Specifically, this study investigated anti-wear properties of different oil additives to create a more robust refrigeration system. Many different additives and concentrations were considered and screened. Pending a successful screen test; these different additives’ anti-wear properties were analyzed using bench top tribology tests. To reduce uncertainty and provide more in-situ results the different additives were operated in a refrigerant compressor on a gas-loop testing apparatus. Oil samples were taken periodically during the test duration for analysis. Lastly, upon test completion the compressors were dismantled and the parts were examined to determine the effectiveness of the anti-wear additives.

Comprehensive Compressor Calorimeter Testing of Lower-GWP Alternative Refrigerants for Heat Pump and Medium Temperature Refrigeration Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shrestha, Som S; Sharma, Vishaldeep; Abdelaziz, Omar

In response to environmental concerns raised by the use of refrigerants with high Global Warming Potential (GWP), the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) has launched an industry-wide cooperative research program, referred to as the Low-GWP Alternative Refrigerants Evaluation Program (AREP), to identify and evaluate promising alternative refrigerants for major product categories. This paper reports one of the Oak Ridge National Laboratory (ORNL) contributions to AREP. It compares performance of alternative refrigerants to that of R-410A and R-404A for heat pump and medium temperature applications, respectively. The alternatives reported in this paper are: R-32, DR-5, and L-41a for R-410A andmore » ARM-31a, D2Y-65, L-40, and a mixture of R-32 and R-134a for R-404A. All performance comparison tests were conducted using scroll compressors of ~1.85 tons (6.5 kW) cooling capacity. Tests were conducted over a range of combinations of saturation suction and saturation discharge temperatures for both compressors. The tests showed that, in general, energy efficiency ratio (EER) and cooling capacity of R-410A alternative refrigerants were slightly lower than that of the baseline refrigerant with a moderate increases in discharge temperature. On the other hand, R-404A alternative refrigerants showed relative performance dependence on saturation suction and saturation discharge temperatures and larger increases in discharge temperature than for the R-410A alternatives. This paper summarizes the relative performance of all alternative refrigerants compared to their respective baseline.« less

Quantum-circuit refrigerator

NASA Astrophysics Data System (ADS)

Tan, Kuan Yen; Partanen, Matti; Lake, Russell E.; Govenius, Joonas; Masuda, Shumpei; Möttönen, Mikko

2017-05-01

Quantum technology promises revolutionizing applications in information processing, communications, sensing and modelling. However, efficient on-demand cooling of the functional quantum degrees of freedom remains challenging in many solid-state implementations, such as superconducting circuits. Here we demonstrate direct cooling of a superconducting resonator mode using voltage-controllable electron tunnelling in a nanoscale refrigerator. This result is revealed by a decreased electron temperature at a resonator-coupled probe resistor, even for an elevated electron temperature at the refrigerator. Our conclusions are verified by control experiments and by a good quantitative agreement between theory and experimental observations at various operation voltages and bath temperatures. In the future, we aim to remove spurious dissipation introduced by our refrigerator and to decrease the operational temperature. Such an ideal quantum-circuit refrigerator has potential applications in the initialization of quantum electric devices. In the superconducting quantum computer, for example, fast and accurate reset of the quantum memory is needed.

Refrigeration system with a compressor-pump unit and a liquid-injection desuperheating line

DOEpatents

Gaul, Christopher J.

2001-01-01

The refrigeration system includes a compressor-pump unit and/or a liquid-injection assembly. The refrigeration system is a vapor-compression refrigeration system that includes an expansion device, an evaporator, a compressor, a condenser, and a liquid pump between the condenser and the expansion device. The liquid pump improves efficiency of the refrigeration system by increasing the pressure of, thus subcooling, the liquid refrigerant delivered from the condenser to the expansion device. The liquid pump and the compressor are driven by a single driving device and, in this regard, are coupled to a single shaft of a driving device, such as a belt-drive, an engine, or an electric motor. While the driving device may be separately contained, in a preferred embodiment, the liquid pump, the compressor, and the driving device (i.e., an electric motor) are contained within a single sealable housing having pump and driving device cooling paths to subcool liquid refrigerant discharged from the liquid pump and to control the operating temperature of the driving device. In another aspect of the present invention, a liquid injection assembly is included in a refrigeration system to divert liquid refrigerant from the discharge of a liquid pressure amplification pump to a compressor discharge pathway within a compressor housing to desuperheat refrigerant vapor to the saturation point within the compressor housing. The liquid injection assembly includes a liquid injection pipe with a control valve to meter the volume of diverted liquid refrigerant. The liquid injection assembly may also include a feedback controller with a microprocessor responsive to a pressure sensor and a temperature sensor both positioned between the compressor to operate the control valve to maintain the refrigerant at or near saturation.

Experimental comparison between R409A and R437A performance in a heat pump unit

NASA Astrophysics Data System (ADS)

Duarte, M. V.; Pires, L. C.; Silva, P. D.; Gaspar, P. D.

2017-04-01

This paper reports an experimental comparison between the use of the refrigerants R409A and R437A in a heat pump unit designed and developed to work with R12. Although the use of both refrigerants in new equipments were abolished in EU and US according the new F-Gas Regulation of EU and SNAP, they still being used as options for R12 in old equipments, especially in developing countries. Both refrigerants were studied for the same test conditions, according to two groups of tests: group A (variation of the heat source temperature) and group B (variation of refrigerant flow rate). The results obtained showed that the R437A presents a higher discharge pressure and a lower discharge temperature. The heating and cooling capacities of both refrigerants were similar, as well as the exergetic efficiency. For the group A of tests the COP of both refrigerants was similar and for the group B of tests the R409A presented an average COP 15% higher. According to the results obtained it is recommended the use of R409A in old equipments (as transition refrigerant) until the acquisition of equipments operating with refrigerants with low-GWP becomes technically and economic feasible.

Field testing energy-saving hermetic compressors in residential refrigerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sauber, R.S.; Middleton, M.G.

The design of an energy-saving compressor for low back pressure applications is reviewed. Calorimeter performance results are stated for two sizes of the efficient design and compared with performance test results for a standard compressor. Power consumption of a refrigerator-freezer is given with a standard compressor and with the energy-saving compressor. The preparation of the refrigerators used in the field test is discussed, along with the criteria used in selecting the instrumentation for the project. Results of the energy-saving compressor in the field test, along with a comparison to a standard production compressor, are presented. Some conclusions are drawn, basedmore » on the data, in relation to important factors in residential refrigerator power consumption.« less

Field testing energy-saving hermetic compressors in residential refrigerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sauber, R.S.; Middleton, M.G.

The design of an energy saving compressor for low back pressure applications is reviewed. Calorimeter performance results are stated for two sizes of the efficient design and compared with performance test results for a standard compressor. Power consumption of a refrigerator-freezer is given with a standard compressor and with the energy saving compressor. The preparation of the refrigerators used in the field test are discussed along with the criteria used in selecting the instrumentation for the project. Results of the energy saving compressor in the field test along with a comparison to a standard production compressor are presented. Some conclusionsmore » are drawn, based on the data, in relation to important factors in residential refrigerator power consumption.« less

Low temperature London penetration depth and superfluid density in Fe-based superconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Hyunsoo

2013-01-01

The superconducting gap symmetry of the Fe-based superconductors was studied by measurements and analysis of London penetration depth and super uid density. Tunnel diode resonator technique for these measurements was implemented in a dilution refrigerator allowing for the temperatures down to 50 mK. For the analysis of the super uid density, we used both experimental studies of Al-coated samples and original thermodynamic approach based on Rutgers relation. In three systems studied, we found that the superconducting gap at the optimal doping is best described in multi-gap full gap scenario. By performing experiments on samples with arti cially introduced disorder withmore » heavy ion irradiation, we show that evolution of the superconducting transition temperature and of the super uid density are consistent with full-gap sign changing s superconducting state. The superconducting gap develops strong modulation both in the under-doped and the over-doped regimes. In the terminal hole-doped KFe{sub 2}As{sub 2}, both temperature dependence of the super uid density and its evolution with increase of the scattering rate are consistent with symmetry imposed vertical line nodes in the superconducting gap. By comparative studies of hole-doped (Ba,K)Fe{sub 2}As{sub 2} and electron-doped Ca10-3-8, we show that the superconducting gap modulation in the under-doped regime is intrinsic and is not induced by the coexisting static magnetic order.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Bo; Abdelaziz, Omar

R410A has no ozone depletion potential (ODP), and is the most commonly used refrigerant in vapor compression systems for space cooling and heating applications. However, it has significant global warming potential with GWP higher than 1900. To mitigate the global warming effect, industry and research institutes are actively pursuing a replacement for R-410A with the following attributes, much lower GWP along with similar or higher efficiency and capacity. DR-55 (aka R452B) is a design-compatible refrigerant replacement for R-410A. It decreases the GWP by 70%, and has lower working pressure, comparable discharge temperature, and uses the same lubricant, tubing, and valves.more » In this study, we experimentally evaluated the performance of DR-55 as a drop-in replacement for R-410A in a high efficiency rooftop air conditioning unit. The experimental results demonstrated that DR-55 led to 5% higher efficiency at the working conditions of Integrated Energy Efficiency Rating (IEER). DR-55 also showed significantly better high ambient performance from 95 F to 125 F. In addition to the experimental study, we used the DOE/ORNL Heat Pump Design Model to model the RTU using R-410A and DR-55, respectively. The model results were compared to the laboratory measurements. The model validation demonstrates that the refrigerant heat transfer and pressure drop correlations, developed for conventional refrigerants like R-410A, are usable for DR-55. Also, a converted compressor model for DR-55, i.e. reducing volumetric and isentropic efficiencies as a function of the suction and discharge pressures from an R-410A compressor map can predict the compressor mass flow rate and power accurately.« less

Thermodynamic design of hydrogen liquefaction systems with helium or neon Brayton refrigerator

NASA Astrophysics Data System (ADS)

Chang, Ho-Myung; Ryu, Ki Nam; Baik, Jong Hoon

2018-04-01

A thermodynamic study is carried out for the design of hydrogen liquefaction systems with helium (He) or neon (Ne) Brayton refrigerator. This effort is motivated by our immediate goal to develop a small-capacity (100 L/h) liquefier for domestic use in Korea. Eight different cycles are proposed and their thermodynamic performance is investigated in comparison with the existing liquefaction systems. The proposed cycles include the standard and modified versions of He Brayton refrigerators whose lowest temperature is below 20 K. The Brayton refrigerator is in direct thermal contact with the hydrogen flow at atmospheric pressure from ambient-temperature gas to cryogenic liquid. The Linde-Hampson system pre-cooled by a Ne Brayton refrigerator is also considered. Full cycle analysis is performed with the real properties of fluids to estimate the figure of merit (FOM) under an optimized operation condition. It is concluded that He Brayton refrigerators are feasible for this small-scale liquefaction, because a reasonably high efficiency can be achieved with simple and safe (low-pressure) operation. The complete cycles with He Brayton refrigerator are presented for the development of a prototype, including the ortho-to-para conversion.

Technical and Economical Demands on 25K - 77K Refrigerators for Future HTS — Series Products in Power Engineering

NASA Astrophysics Data System (ADS)

Gromoll, B.

2004-06-01

For the future high temperature superconductivity, HTS, series products new refrigerators are essential. Demands are made on these which are only partly fulfilled by refrigerators available in the market today. This refers to cooling power, initial cost and in particular reliability. Without proper refrigeration techniques it will be almost impossible to bring HTS products to the market. Based on the experiences made by the construction and operation of HTS prototypes within our company, like the 400 kW motor, 1.2 MVA current limiter and 1 MVA traction-transformer provided with refrigerators which are available in the market today, criteria have been established to identify the future technical and economical requirements. These criteria apply to efficiency, maintainability, operation flexibility, feasibility of integration and performance/cost ratio. For the temperature range of 20 K to 77 K cooling with Gifford-McMahon, Pulse Tube, Stirling and Mixture-Cascade refrigerators are applicable. The development potential of these processes are compared for the different applications in future series products. Presented are the necessary steps towards reliable and economic refrigerators from the viewpoint of an equipment manufacturer. These are essential for a market entry in the year 2008.

Tuning the electrocaloric enhancement near the morphotropic phase boundary in lead-free ceramics

NASA Astrophysics Data System (ADS)

Le Goupil, Florian; McKinnon, Ruth; Koval, Vladimir; Viola, Giuseppe; Dunn, Steve; Berenov, Andrey; Yan, Haixue; Alford, Neil Mcn.

2016-06-01

The need for more energy-efficient and environmentally-friendly alternatives in the refrigeration industry to meet global emission targets has driven efforts towards materials with a potential for solid state cooling. Adiabatic depolarisation cooling, based on the electrocaloric effect (ECE), is a significant contender for efficient new solid state refrigeration techniques. Some of the highest ECE performances reported are found in compounds close to the morphotropic phase boundary (MPB). This relationship between performance and the MPB makes the ability to tune the position of the MPB an important challenge in electrocaloric research. Here, we report direct ECE measurements performed on MPB tuned NBT-06BT bulk ceramics with a combination of A-site substitutions. We successfully shift the MPB of these lead-free ceramics closer to room temperature, as required for solid state refrigeration, without loss of the criticality of the system and the associated ECE enhancement.

Tuning the electrocaloric enhancement near the morphotropic phase boundary in lead-free ceramics

PubMed Central

Le Goupil, Florian; McKinnon, Ruth; Koval, Vladimir; Viola, Giuseppe; Dunn, Steve; Berenov, Andrey; Yan, Haixue; Alford, Neil McN.

2016-01-01

The need for more energy-efficient and environmentally-friendly alternatives in the refrigeration industry to meet global emission targets has driven efforts towards materials with a potential for solid state cooling. Adiabatic depolarisation cooling, based on the electrocaloric effect (ECE), is a significant contender for efficient new solid state refrigeration techniques. Some of the highest ECE performances reported are found in compounds close to the morphotropic phase boundary (MPB). This relationship between performance and the MPB makes the ability to tune the position of the MPB an important challenge in electrocaloric research. Here, we report direct ECE measurements performed on MPB tuned NBT-06BT bulk ceramics with a combination of A-site substitutions. We successfully shift the MPB of these lead-free ceramics closer to room temperature, as required for solid state refrigeration, without loss of the criticality of the system and the associated ECE enhancement. PMID:27312287

Enhanced electrocaloric analysis and energy-storage performance of lanthanum modified lead titanate ceramics for potential solid-state refrigeration applications.

PubMed

Zhang, Tian-Fu; Huang, Xian-Xiong; Tang, Xin-Gui; Jiang, Yan-Ping; Liu, Qiu-Xiang; Lu, Biao; Lu, Sheng-Guo

2018-01-10

The unique properties and great variety of relaxer ferroelectrics make them highly attractive in energy-storage and solid-state refrigeration technologies. In this work, lanthanum modified lead titanate ceramics are prepared and studied. The giant electrocaloric effect in lanthanum modified lead titanate ceramics is revealed for the first time. Large refrigeration efficiency (27.4) and high adiabatic temperature change (1.67 K) are achieved by indirect analysis. Direct measurements of electrocaloric effect show that reversible adiabatic temperature change is also about 1.67 K, which exceeds many electrocaloric effect values in current direct measured electrocaloric studies. Both theoretical calculated and direct measured electrocaloric effects are in good agreements in high temperatures. Temperature and electric field related energy storage properties are also analyzed, maximum energy-storage density and energy-storage efficiency are about 0.31 J/cm 3 and 91.2%, respectively.

Cascade Reverse Osmosis Air Conditioning System: Cascade Reverse Osmosis and the Absorption Osmosis Cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

BEETIT Project: Battelle is developing a new air conditioning system that uses a cascade reverse osmosis (RO)-based absorption cycle. Analyses show that this new cycle can be as much as 60% more efficient than vapor compression, which is used in 90% of air conditioners. Traditional vapor-compression systems use polluting liquids for a cooling effect. Absorption cycles use benign refrigerants such as water, which is absorbed in a salt solution and pumped as liquid—replacing compression of vapor. The refrigerant is subsequently separated from absorbing salt using heat for re-use in the cooling cycle. Battelle is replacing thermal separation of refrigerant withmore » a more efficient reverse osmosis process. Research has shown that the cycle is possible, but further investment will be needed to reduce the number of cascade reverse osmosis stages and therefore cost.« less

Tuning the electrocaloric enhancement near the morphotropic phase boundary in lead-free ceramics.

PubMed

Le Goupil, Florian; McKinnon, Ruth; Koval, Vladimir; Viola, Giuseppe; Dunn, Steve; Berenov, Andrey; Yan, Haixue; Alford, Neil McN

2016-06-17

The need for more energy-efficient and environmentally-friendly alternatives in the refrigeration industry to meet global emission targets has driven efforts towards materials with a potential for solid state cooling. Adiabatic depolarisation cooling, based on the electrocaloric effect (ECE), is a significant contender for efficient new solid state refrigeration techniques. Some of the highest ECE performances reported are found in compounds close to the morphotropic phase boundary (MPB). This relationship between performance and the MPB makes the ability to tune the position of the MPB an important challenge in electrocaloric research. Here, we report direct ECE measurements performed on MPB tuned NBT-06BT bulk ceramics with a combination of A-site substitutions. We successfully shift the MPB of these lead-free ceramics closer to room temperature, as required for solid state refrigeration, without loss of the criticality of the system and the associated ECE enhancement.

Glycolysis recycling of rigid waste polyurethane foam from refrigerators.

PubMed

Zhu, P; Cao, Z B; Chen, Y; Zhang, X J; Qian, G R; Chu, Y L; Zhou, M

2014-01-01

Rapid growth of rigid waste polyurethane (WPUR) foam from refrigerators attracts the attention all over the world. In this study, glycolysis was chosen to treat WPUR from scrapped refrigerators collected in Shanghai, China. Glycolysis reagents and catalysts were selected. The results indicated that the glycolysis efficiency of ethylene glycol (EG) was higher than that of diethylene glycol, and the catalytic efficiency of alkali metal salts (NaOH) was more excellent than that of triethanolamine and organic salts of alkali metal (NaAc). When EG was 100%WPUR as a glycolysis reagent and NaOH was 1%WPUR as a catalyst at a constant temperature of 197.85°C for 2 h, the glycolysis product had the highest glycolysis conversion rate. In order to maximize the recycling of WPUR, regenerative Polyurethane was performed by adding 10% distilled mixed polyol, which conformed to the QB/T 26689-2011 requirements.

Heat pump/refrigerator using liquid working fluid

DOEpatents

Wheatley, John C.; Paulson, Douglas N.; Allen, Paul C.; Knight, William R.; Warkentin, Paul A.

1982-01-01

A heat transfer device is described that can be operated as a heat pump or refrigerator, which utilizes a working fluid that is continuously in a liquid state and which has a high temperature-coefficient of expansion near room temperature, to provide a compact and high efficiency heat transfer device for relatively small temperature differences as are encountered in heating or cooling rooms or the like. The heat transfer device includes a pair of heat exchangers that may be coupled respectively to the outdoor and indoor environments, a regenerator connecting the two heat exchangers, a displacer that can move the liquid working fluid through the heat exchangers via the regenerator, and a means for alternately increasing and decreasing the pressure of the working fluid. The liquid working fluid enables efficient heat transfer in a compact unit, and leads to an explosion-proof smooth and quiet machine characteristic of hydraulics. The device enables efficient heat transfer as the indoor-outdoor temperature difference approaches zero, and enables simple conversion from heat pumping to refrigeration as by merely reversing the direction of a motor that powers the device.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shah, Nihar K.; Wei, Max; Letschert, Virginie

Hydrofluorocarbons (HFCs) emitted from uses such as refrigerants and thermal insulating foam, are now the fastest growing greenhouse gases (GHGs), with global warming potentials (GWP) thousands of times higher than carbon dioxide (CO2). Because of the short lifetime of these molecules in the atmosphere,1 mitigating the amount of these short-lived climate pollutants (SLCPs) provides a faster path to climate change mitigation than control of CO2 alone. This has led to proposals from Africa, Europe, India, Island States, and North America to amend the Montreal Protocol on Substances that Deplete the Ozone Layer (Montreal Protocol) to phase-down high-GWP HFCs. Simultaneously, energymore » efficiency market transformation programs such as standards, labeling and incentive programs are endeavoring to improve the energy efficiency for refrigeration and air conditioning equipment to provide life cycle cost, energy, GHG, and peak load savings. In this paper we provide an estimate of the magnitude of such GHG and peak electric load savings potential, for room air conditioning, if the refrigerant transition and energy efficiency improvement policies are implemented either separately or in parallel.« less

High Efficiency Low Global Warming Potential Compressor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cogswell, Frederick; Verma, Parmesh

During this project UTRC designed a novel compressor for use with new low Global-Warming-Potential (GWP) refrigerants. Through two design and testing iterations, UTRC advanced the compressor technology from TRL3 to TRL5. The target application was a 5 Tons of Refrigeration (TR) capacity Roof-Top Unit (RTU), although this technology may be applied to other low-capacity systems such as residential. The prototype unit met all design goals at the ARI-A rating condition and requires high efficiency motor to meet high performance targets at the ARI-B condition. This technology may be used in high efficiency units and with seasonal energy efficiency rating (SEER)more » exceeding 20. A preliminary cost analysis estimated that there would be less than $25/kbtuh cost impact to the customer.« less

Dual stage active magnetic regenerator and method

DOEpatents

Pecharsky, V.K.; Gschneidner, K.A. Jr.

1999-03-30

A dual stage active magnetic regenerator refrigerator as well as method using the Joule-Brayton thermodynamic cycle includes a high temperature stage refrigerant comprising DyAl{sub 2} or (Dy{sub 1{minus}x}Er{sub x})Al{sub 2} where x is selected to be greater than 0 and less than about 0.3 in combination with a low temperature stage comprising (Dy{sub 1{minus}x}Er{sub x})Al{sub 2} where x is selected to be greater than about 0.5 and less than 1 to provide significantly improved refrigeration efficiency in the liquefaction of gaseous hydrogen. 17 figs.

Dual stage active magnetic regenerator and method

DOEpatents

Pecharsky, Vitalij K.; Gschneidner, Jr., Karl A.

1999-03-30

A dual stage active magnetic regenerator refrigerator as well as method using the Joule-Brayton thermodynamic cycle includes a high temperature stage refrigerant comprising DyAl.sub.2 or (Dy.sub.1-x Er.sub.x)Al.sub.2 where x is selected to be greater than 0 and less than about 0.3 in combination with a low temperature stage comprising (Dy.sub.1-x Er.sub.x)Al.sub.2 where x is selected to be greater than about 0.5 and less than 1 to provide significantly improved refrigeration efficiency in the liquefaction of gaseous hydrogen.

Room-temperature semiconductor heterostructure refrigeration

NASA Astrophysics Data System (ADS)

Chao, K. A.; Larsson, Magnus; Mal'shukov, A. G.

2005-07-01

With the proper design of semiconductor tunneling barrier structures, we can inject low-energy electrons via resonant tunneling, and take out high-energy electrons via a thermionic process. This is the operation principle of our semiconductor heterostructure refrigerator (SHR) without the need of applying a temperature gradient across the device. Even for the bad thermoelectric material AlGaAs, our calculation shows that at room temperature, the SHR can easily lower the temperature by 5-7K. Such devices can be fabricated with the present semiconductor technology. Besides its use as a kitchen refrigerator, the SHR can efficiently cool microelectronic devices.

Advancement of Double Effect Absorption Cycle by Input of Low Temperature Waste Heat

NASA Astrophysics Data System (ADS)

Kojima, Hiroshi; Edera, Masaru; Nakamura, Makoto; Oka, Masahiro; Akisawa, Atsushi; Kashiwagi, Takao

Energy conservation is becoming important for global environmental protection. New simple techniques of more efficient1y using the waste heat of gas co-generation systems for refrigerationare required. In first report, a new method of using the low temperature waste heat for refrigeration was proposed, and the basic characteristics of the promising methods of recovering waste heat were c1arified. In this report, the more detailed simulation model of the series flow type double effect absorption refrigerator with auxiliary heat exchanger was constructed and the static characteristics were investigated. Then experiments on this advanced absorption refrigerator were carried out, and the results of the calculation and experiments were compared and discussed. Moreover, the betterment of the simulation model of this advanced absorption refrigerator was carried out.

Thermodynamic feature of a Brownian heat engine operating between two heat baths.

PubMed

Asfaw, Mesfin

2014-01-01

A generalized theory of nonequilibrium thermodynamics for a Brownian motor operating between two different heat baths is presented. Via a simple paradigmatic model, we not only explore the thermodynamic feature of the engine in the regime of the nonequilibrium steady state but also study the short time behavior of the system for either the isothermal case with load or, in general, the nonisothermal case with or without load. Many elegant thermodynamic theories can be checked via the present model. Furthermore the dependence of the velocity, the efficiency, and the performance of the refrigerator on time t is examined. Our study reveals a current reversal due to time t. In the early system relaxation period, the model works neither as a heat engine nor as a refrigerator and only after a certain period of time does the model start functioning as a heat engine or as a refrigerator. The performance of the engine also improves with time and at steady state the engine manifests a higher efficiency or performance as a refrigerator. Furthermore the effect of energy exchange via the kinetic energy on the performance of the heat engine is explored.

Potential Alternative Lower Global Warming Refrigerants for Air Conditioning in Hot Climates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelaziz, Omar; Shrestha, Som S; Shen, Bo

The earth continues to see record increase in temperatures and extreme weather conditions that is largely driven by anthropogenic emissions of warming gases such as carbon dioxide and other more potent greenhouse gases such as refrigerants. The cooperation of 188 countries in the Conference of the Parties in Paris 2015 (COP21) resulted in an agreement aimed to achieve a legally binding and universal agreement on climate, with the aim of keeping global warming below 2 C. A global phasedown of hydrofluorocarbons (HFCs) can prevent 0.5 C of warming by 2100. However, most of the countries in hot climates are consideredmore » as developing countries and as such are still using R-22 (a Hydrochlorofluorocarbon (HCFC)) as the baseline refrigerant and are currently undergoing a phase-out of R-22 which is controlled by current Montreal Protocol to R-410A and other HFC based refrigerants. These HFCs have significantly high Global Warming Potential (GWP) and might not perform as well as R-22 at high ambient temperature conditions. In this paper we present recent results on evaluating the performance of alternative lower GWP refrigerants for R-22 and R-410A for small residential mini-split air conditioners and large commercial packaged units. Results showed that several of the alternatives would provide adequate replacement for R-22 with minor system modification. For the R-410A system, results showed that some of the alternatives were almost drop-in ready with benefit in efficiency and/or capacity. One of the most promising alternatives for R-22 mini-split unit is propane (R-290) as it offers higher efficiency; however it requires compressor and some other minor system modification to maintain capacity and minimize flammability risk. Between the R-410A alternatives, R-32 appears to have a competitive advantage; however at the cost of higher compressor discharge temperature. With respect to the hydrofluoroolefin (HFO) blends, there existed a tradeoff in performance and system design. It was noticed that higher glide refrigerants benefited the most from operating in the larger packaged unit with an evaporator in a multi-row counter-cross configuration. This study suggests that there is a strong potential for using lower GWP refrigerants to design and operate more efficient air conditioning systems in hot climates.« less

78 FR 1570 - Semiannual Regulatory Agenda

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-08

... Transformers (energy efficiency standards) Residential clothes washers (energy efficiency standards... Distribution Transformers (Reg Plan Seq No. 32). 263 Test Procedures for 1904-AC76 Residential Refrigerators... Efficiency Standards for Distribution Transformers Regulatory Plan: This entry is Seq. No. 32 in part II of...

Model validations for low-global warming potential refrigerants in mini-split air-conditioning units

DOE PAGES

Shen, Bo; Shrestha, Som; Abdelaziz, Omar

2016-09-02

To identify low GWP (global warming potential) refrigerants to replace R-22 and R-410A, extensive experimental evaluations were conducted for multiple candidates of refrigerant at the standard test conditions and at high-ambient conditions with outdoor temperature varying from 27.8 C to 55.0 C.. In the study, R-22 was compared to propane (R-290), DR-3, ARM-20B, N-20B and R-444B in a mini-split air conditioning unit originally designed for R-22; R-410A was compared to R-32, DR-55, ARM-71A, L41-2 (R-447A) in a mini-split unit designed for R-410A. To reveal physics behind the measured performance results, thermodynamic properties of the alternative refrigerants were analysed. In addition,more » the experimental data was used to calibrate a physics-based equipment model, i.e. ORNL Heat Pump Design Model (HPDM). The calibrated model translated the experimental results to key calculated parameters, i.e. compressor efficiencies, refrigerant side two-phase heat transfer coefficients, corresponding to each refrigerant. As a result, these calculated values provide scientific insights on the performance of the alternative refrigerants and are useful for other applications beyond mini-split air conditioning units.« less

SBIR Grant:No-Vibration Agile Cryogenic Optical Refrigerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Epstein, Richard

2013-04-09

Optical refrigeration is currently the only all-solid-state cryocooling technology that has been demonstrated. Optical cryocoolers are devices that use laser light to cool small crystal or glass cooling elements. The cooling element absorbs the laser light and reradiates it at higher energy, an example of anti-Stokes fluorescence. The dif-ference between the energy of the outgoing and incoming light comes from the thermal energy of the cooling element, which in turn becomes colder. Entitled No-Vibration Agile Cryocoolers using Optical Refrigeration, this Phase I proposal directly addressed the continued development of the optical refrigerator components necessary to transition this scientific breakthrough intomore » National Nu-clear Security Administration (NNSA) sensor applications in line with the objectives of topic 50b. ThermoDynamic Films LLC (TDF), in collaboration with the University of New Mexico (UNM), cooled an optical-refrigerator cooling element comprised of an ytterbium-doped yttrium lithium fluoride (Yb:YLF) crystal from room tempera-ture to 123 K with about 2% efficiency. This is the world record in optical refrigera-tion and an important step toward revolutionizing cryogenic systems for sensor ap-plications. During this period, they also designed and analyzed the crucial elements of a prototype optical refrigerator including the thermal link that connects the cool-ing element with the load.« less

Model validations for low-global warming potential refrigerants in mini-split air-conditioning units

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Bo; Shrestha, Som; Abdelaziz, Omar

To identify low GWP (global warming potential) refrigerants to replace R-22 and R-410A, extensive experimental evaluations were conducted for multiple candidates of refrigerant at the standard test conditions and at high-ambient conditions with outdoor temperature varying from 27.8 C to 55.0 C.. In the study, R-22 was compared to propane (R-290), DR-3, ARM-20B, N-20B and R-444B in a mini-split air conditioning unit originally designed for R-22; R-410A was compared to R-32, DR-55, ARM-71A, L41-2 (R-447A) in a mini-split unit designed for R-410A. To reveal physics behind the measured performance results, thermodynamic properties of the alternative refrigerants were analysed. In addition,more » the experimental data was used to calibrate a physics-based equipment model, i.e. ORNL Heat Pump Design Model (HPDM). The calibrated model translated the experimental results to key calculated parameters, i.e. compressor efficiencies, refrigerant side two-phase heat transfer coefficients, corresponding to each refrigerant. As a result, these calculated values provide scientific insights on the performance of the alternative refrigerants and are useful for other applications beyond mini-split air conditioning units.« less

Effect of Water Quality and Temperature on the Efficiency of Two Kinds of Hydrophilic Polymers in Soil.

PubMed

Dehkordi, Davoud Khodadadi

2018-06-01

  In this study, evaluation of two-superabsorbent effects, Super-AB-A-300 and Super-AB-A-200 in a sandy soil on the water retention capability and saturated hydraulic conductivity (Ks) at different water quality and soil temperature were done. The Super-AB-A-200 was less effective in water uptake than Super-AB-A-300. The efficiency of these polymers in water retention was negatively influenced by the water quality and temperature. The efficiency of these polymer treatments in water uptake reduced significantly (P < 0.05) with increasing soil temperature. In the control soil, the Ks stayed nearly constant with increasing soil temperature. As compared to the untreated control, the treated soil demonstrated a significant (P < 0.05) linear increase of Ks with increasing soil temperature. In the control soil, the water holding properties curve did not change with increasing soil temperature.

Demonstration of a high-capacity turboalternator for a 20 K, 20 W space-borne Brayton cryocooler

NASA Astrophysics Data System (ADS)

Zagarola, M.; Cragin, K.; Deserranno, D.

2014-01-01

NASA is considering multiple missions involving long-term cryogenic propellant storage in space. Liquid hydrogen and oxygen are the typical cryogens as they provide the highest specific impulse of practical chemical propellants. Storage temperatures are nominally 20 K for liquid hydrogen and 90 K for liquid oxygen. Heat loads greater than 10 W at 20 K are predicted for hydrogen storage. Current space cryocoolers have been developed for sensor cooling with refrigeration capacities less than 1 W at 20 K. In 2011, Creare Inc. demonstrated an ultra-low-capacity turboalternator for use in a turbo-Brayton cryocooler. The turboalternator produced up to 5 W of turbine refrigeration at 20 K; equivalent to approximately 3 W of net cryocooler refrigeration. This turboalternator obtained unprecedented operating speeds and efficiencies at low temperatures benefitting from new rotor design and fabrication techniques, and new bearing fabrication techniques. More recently, Creare applied these design and fabrication techniques to a larger and higher capacity 20 K turboalternator. The turboalternator was tested in a high-capacity, low temperature test facility at Creare and demonstrated up to 42 W of turbine refrigeration at 20 K; equivalent to approximately 30 W of net cryocooler refrigeration. The net turbine efficiency was the highest achieved to date at Creare for a space-borne turboalternator. This demonstration was the first step in the development of a high-capacity turbo-Brayton cryocooler for liquid hydrogen storage. In this paper, we will review the design, development and testing of the turboalternator.

High efficiency novel window air conditioner

DOE PAGES

Bansal, Pradeep

2015-07-24

This paper presents the technical development of a high efficiency window air conditioner. In order to achieve higher energy efficiency ratio (EER), the original capacity of the R410A unit was downgraded by replacing the original compressor with a lower capacity but higher EER compressor, while all heat exchangers and the chassis from the original unit were retained. The other subsequent major modifications included – the AC fan motor being replaced with a brushless high efficiency electronically commuted motor (ECM) motor, the capillary tube being replaced with a needle valve to better control the refrigerant flow and refrigerant set points, andmore » R410A being replaced with drop-in environmentally friendly binary mixture of R32 (85% molar concentration)/R125 (15% molar concentration). All these modifications resulted in significant EER enhancement of the modified unit.« less

High efficiency novel window air conditioner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bansal, Pradeep

This paper presents the technical development of a high efficiency window air conditioner. In order to achieve higher energy efficiency ratio (EER), the original capacity of the R410A unit was downgraded by replacing the original compressor with a lower capacity but higher EER compressor, while all heat exchangers and the chassis from the original unit were retained. The other subsequent major modifications included – the AC fan motor being replaced with a brushless high efficiency electronically commuted motor (ECM) motor, the capillary tube being replaced with a needle valve to better control the refrigerant flow and refrigerant set points, andmore » R410A being replaced with drop-in environmentally friendly binary mixture of R32 (85% molar concentration)/R125 (15% molar concentration). All these modifications resulted in significant EER enhancement of the modified unit.« less

A novel vortex tube-based N2-expander liquefaction process for enhancing the energy efficiency of natural gas liquefaction

NASA Astrophysics Data System (ADS)

Qyyum, Muhammad Abdul; Wei, Feng; Hussain, Arif; Ali, Wahid; Sehee, Oh; Lee, Moonyong

2017-11-01

This research work unfolds a simple, safe, and environment-friendly energy efficient novel vortex tube-based natural gas liquefaction process (LNG). A vortex tube was introduced to the popular N2-expander liquefaction process to enhance the liquefaction efficiency. The process structure and condition were modified and optimized to take a potential advantage of the vortex tube on the natural gas liquefaction cycle. Two commercial simulators ANSYS® and Aspen HYSYS® were used to investigate the application of vortex tube in the refrigeration cycle of LNG process. The Computational fluid dynamics (CFD) model was used to simulate the vortex tube with nitrogen (N2) as a working fluid. Subsequently, the results of the CFD model were embedded in the Aspen HYSYS® to validate the proposed LNG liquefaction process. The proposed natural gas liquefaction process was optimized using the knowledge-based optimization (KBO) approach. The overall energy consumption was chosen as an objective function for optimization. The performance of the proposed liquefaction process was compared with the conventional N2-expander liquefaction process. The vortex tube-based LNG process showed a significant improvement of energy efficiency by 20% in comparison with the conventional N2-expander liquefaction process. This high energy efficiency was mainly due to the isentropic expansion of the vortex tube. It turned out that the high energy efficiency of vortex tube-based process is totally dependent on the refrigerant cold fraction, operating conditions as well as refrigerant cycle configurations.

Influence of some design parameters on the thermal performance of domestic refrigerator appliances

NASA Astrophysics Data System (ADS)

Rebora, Alessandro; Senarega, Maurizio; Tagliafico, Luca A.

2006-07-01

This paper presents a thermal study on chest-freezers, the small refrigerators used in domestic and supermarket applications. A thermal and energy model of a particular kind of these refrigerators, the “hot-wall” (or “skin condenser”) refrigerator, is developed and used to perform sensitivity and design optimisation analysis for given working temperatures and useful volume of the refrigerated cell. A finite-element heat transfer model of the refrigerator box is coupled to the complete thermodynamic model of the refrigerating plant, including real working conditions (compressor efficiency, friction pressure losses and so on). A sensitivity study of the main design parameters affecting the global refrigerator performance has been developed (for fixed working temperatures) with reference to the thickness of the metallic plates, to the evaporator and condenser tube diameters and to the evaporator tube pitch (with fixed evaporator-to-condenser tube pitch ratio). The results obtained show that the proposed sensitivity analysis can yield quite reliable results (in comparison with much more complex, albeit more accurate mathematical optimisation algorithms) using small computational resources. The great importance of 2-D heat conduction in the metallic plates is shown, evidencing how the plate thickness and the evaporator and condenser tube diameters affect the global performance of the system according to the well-known “fin efficiency” effect. The influence of the evaporator and condenser tube diameters on the friction pressure losses is also outlined. Some practical suggestions are made in conclusion, regarding the criteria which should be adopted in the thermal design of a hot-wall refrigerator.

Experimental investigations and improvements for the 10 K G-M refrigerator

NASA Astrophysics Data System (ADS)

Hao, Xihuan; Ju, Yonglin

2012-06-01

With the wide application of high performance cryo-pumps, high and low temperature superconducting devices, MRI, infrared detectors and cryogenic electronics, the development of high efficient and reliable 10 K G-M refrigerator is of critical importance and awaited by cryogenic industries. In the past two years, systematic studies have been carried out, and detailed experimental tests indicated that the cooling performance of the 10 K G-M refrigerator was improved by adding two additional rectification meshes inside the low temperature regenerator and by optimizing the system charge pressure. Furthermore, a new labyrinth sealing displacer was proposed and fabricated to substitute the traditional piston-ring sealing displacer for improved operating stability and reliability of the 10 K GM refrigerator. The detailed experimental results and improvements were summarized and their optimal cases were given in this paper.

Adsorption Refrigeration System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Kai; Vineyard, Edward Allan

Adsorption refrigeration is an environmentally friendly cooling technology which could be driven by recovered waste heat or low-grade heat such as solar energy. In comparison with absorption system, an adsorption system has no problems such as corrosion at high temperature and salt crystallization. In comparison with vapor compression refrigeration system, it has the advantages of simple control, no moving parts and less noise. This paper introduces the basic theory of adsorption cycle as well as the advanced adsorption cycles such as heat and mass recovery cycle, thermal wave cycle and convection thermal wave cycle. The types, characteristics, advantages and drawbacksmore » of different adsorbents used in adsorption refrigeration systems are also summarized. This article will increase the awareness of this emerging cooling technology among the HVAC engineers and help them select appropriate adsorption systems in energy-efficient building design.« less

Development of an adsorption compressor for use in cryogenic refrigeration

NASA Technical Reports Server (NTRS)

Schember, Helen R.

1989-01-01

A new compressor with no moving parts has been developed which is able to supply a source of high-pressure gas to a Joule-Thompson based cryogenic refrigerator. The compressor relies on a newly implemented combination of high-surface-area Saran carbon (sorbent) and krypton gas (working fluid). In addition, an integral gas-gap heat switch is used to provide improved overall efficiency. A prototype compressor has been designed, built, and tested as a part of the Jet Propulsion Laboratory effort in sorption refrigeration. Performance data from the prototype unit described here demonstrate successful compressor performance and good agreement with theoretical predictions.

'Virgin gas' ban demands user rethink.

PubMed

Baillie, Jonathan

2010-05-01

A-Gas (UK), a leading UK independent blender and distributor of speciality gases and chemicals, says that many users of the highly versatile HCFC 22 (hydrochlorofluorocarbon) refrigerant gas, including hospitals, are still either unaware, or not taking action to address, this year's ban on the use of both virgin R22, and other virgin HCFC refrigerant gases, in equipment such as air conditioning plant. HEJ editor Jonathan Baillie discussed, with senior personnel, the options for existing HCFC users, and discovered that the "virgin" gas ban could present cost-cutting opportunities for those able to purchase new, more energy-efficient plant compatible with the latest replacement hydrofluorocarbon, and other modern refrigerants.

Energy and Exergy Analysis of Vapour Absorption Refrigeration Cycle—A Review

NASA Astrophysics Data System (ADS)

Kanabar, Bhaveshkumar Kantilal; Ramani, Bharatkumar Maganbhai

2016-07-01

In recent years, an energy crisis and the energy consumption have become global problems which restrict the sustainable growth. In these scenarios the scientific energy recovery and the utilization of various kinds of waste heat become very important. The waste heat can be utilized in many ways and one of the best practices is to use it for vapour absorption refrigeration system. To ensure efficient working of absorption cycle and utilization of optimum heat, exergy is the best tool for analysis. This paper provides the comprehensive picture of research and development of absorption refrigeration technology, practical and theoretical analysis with different arrangements of the cycle.

Sub-to super-ambient temperature programmable microfabricated gas chromatography column

DOEpatents

Robinson, Alex L.; Anderson, Lawrence F.

2004-03-16

A sub- to super-ambient temperature programmable microfabricated gas chromatography column enables more efficient chemical separation of chemical analytes in a gas mixture by combining a thermoelectric cooler and temperature sensing on the microfabricated column. Sub-ambient temperature programming enables the efficient separation of volatile organic compounds and super-ambient temperature programming enables the elution of less volatile analytes within a reasonable time. The small heat capacity and thermal isolation of the microfabricated column improves the thermal time response and power consumption, both important factors for portable microanalytical systems.

Identifying lubricant options for compressor bearing designs

NASA Astrophysics Data System (ADS)

Karnaz, J.; Seeton, C.; Dixon, L.

2017-08-01

Today’s refrigeration and air conditioning market is not only driven by the environmental aspects of the refrigerants, but also by the energy efficiency and reliability of system operation. Numerous types of compressor designs are used in refrigeration and air conditioning applications which means that different bearings are used; and in some cases, multiple bearing types within a single compressor. Since only one lubricant is used, it is important to try to optimize the lubricant to meet the various demands and requirements for operation. This optimization entails investigating different types of lubricant chemistries, viscosities, and various formulation options. What makes evaluating these options more challenging is the refrigerant which changes the properties of the lubricant delivered to the bearing. Once the lubricant and refrigerant interaction are understood, through various test methods, then work can start on collaborating with compressor engineers on identifying the lubricant chemistry and formulation options. These interaction properties are important to the design engineer to make decisions on the adequacy of the lubricant before compressor tests are started. This paper will discuss the process to evaluate lubricants for various types of compressors and bearing design with focus on what’s needed for current refrigerant trends. In addition, the paper will show how the lubricant chemistry choice can be manipulated through understanding of the bearing design and knowledge of interaction with the refrigerant to maximize performance. Emphasis will be placed on evaluation of synthetic lubricants for both natural and synthetic low GWP refrigerants.

Redesign 3 R Machine as a Refrigerant Waste Treatment Alternative in Environmental Rescue

NASA Astrophysics Data System (ADS)

Negara, I. P. S.; Arsawan, I. M.

2018-01-01

Cooling machine technologies really affect nowadays’ modern life, not only limited in enhancement of life quality and comfort, but it has also reached the essential things of humans’ life supporter (Arora, 2001). Cooling machine technologies have direct contribution toward environmental damage such as depletion of ozone layer and global warming through synthetic refrigerant waste and leakage (CFC and HFC) to environment. The refrigerant release to the environment is 60% of the service sector. Destructive characteristics of ozone possessed by CFC were first proposed by Rowland and Molina which were then supported by yard measurement. It is estimated that ozone layer damage occurs for about 3% every decade. The ozone layer located in the stratosphere is functioned to prevent ultraviolet-B ray from entering into earth surface. This Ultraviolet-B is suspected to be the cause of health problem for humans and disorder for plants on earth. As for the purpose of this research is to obtain a product design of refrigerant waste processing system (recovery and recycle refrigerant) as well as to acknowledge the work method (COP) of cooling machines that use CFC refrigerant (R-12) as the result of recovery and recycle compared to CFC refrigerant (R-12)/pure R134a. One method that can be used is by redesigning existing equipment namely 3R machine that cannot be used anymore thus it can be reused. This research will be conducted through modifying the existing 3R machine therefore it can be reused and be easily operated as well as doing the maintenance, after that the refrigerant as the result of recovery will be tried on a refrigeration system and a test of refrigeration system work method will be conducted by using the refrigerant recycle product which is obtained and compared with the work method of the one with pure refrigeration.The result has been achieved that the redesign product of refrigerant waste processing equipment can be reused and able to perform the recovery, recycle and richarging process, although using semi-automatic control system. So the use of car air conditioning refrigerant can be more efficient. With the functioning of 3R mesi is expected wastes refrigerant is not wasted which is one of the efforts to save the environment.

High sensitivity spectroscopic and thermal characterization of cooling efficiency for optical refrigeration materials

NASA Astrophysics Data System (ADS)

Melgaard, Seth D.; Seletskiy, Denis V.; Di Lieto, Alberto; Tonelli, Mauro; Sheik-Bahae, Mansoor

2012-03-01

Since recent demonstration of cryogenic optical refrigeration, a need for reliable characterization tools of cooling performance of different materials is in high demand. We present our experimental apparatus that allows for temperature and wavelength dependent characterization of the materials' cooling efficiency and is based on highly sensitive spectral differencing technique or two-band differential spectral metrology (2B-DSM). First characterization of a 5% w.t. ytterbium-doped YLF crystal showed quantitative agreement with the current laser cooling model, as well as measured a minimum achievable temperature (MAT) at 110 K. Other materials and ion concentrations are also investigated and reported here.

Cycle of a closed gas-turbine plant with a gas-dynamic energy-separation device

NASA Astrophysics Data System (ADS)

Leontiev, A. I.; Burtsev, S. A.

2017-09-01

The efficiency of closed gas-turbine space-based plants is analyzed. The weight-size characteristics of closed gas-turbine plants are shown in many respects as determined by the refrigerator-radiator parameters. The scheme of closed gas-turbine plants with a gas-dynamic temperature-stratification device is proposed, and a calculation model is developed. This model shows that the cycle efficiency decreases by 2% in comparison with that of the closed gas-turbine plants operating by the traditional scheme with increasing temperature at the output from the refrigerator-radiator by 28 K and decreasing its area by 13.7%.

Using solar-powered refrigeration for vaccine storage where other sources of reliable electricity are inadequate or costly.

PubMed

McCarney, Steve; Robertson, Joanie; Arnaud, Juliette; Lorenson, Kristina; Lloyd, John

2013-12-09

Large areas of many developing countries have no grid electricity. This is a serious challenge that threatens the continuity of the vaccine cold chain. The main alternatives to electrically powered refrigerators available for many years--kerosene- and gas-driven refrigerators--are plagued by problems with gas supply interruptions, low efficiency, poor temperature control, and frequent maintenance needs. There are currently no kerosene- or gas-driven refrigerators that qualify under the minimum standards established by the World Health Organization (WHO) Performance, Quality, and Safety (PQS) system. Solar refrigeration was a promising development in the early 1980s, providing an alternative to absorption technology to meet cold chain needs in remote areas. Devices generally had strong laboratory performance data; however, experience in the field over the years has been mixed. Traditional solar refrigerators relied on relatively expensive battery systems, which have demonstrated short lives compared to the refrigerator. There are now alternatives to the battery-based systems and a clear understanding that solar refrigerator systems need to be designed, installed, and maintained by technicians with the necessary knowledge and training. Thus, the technology is now poised to be the refrigeration method of choice for the cold chain in areas with no electricity or extremely unreliable electricity (less than 4h per average day) and sufficient sunlight. This paper highlights some lessons learned with solar-powered refrigeration, and discusses some critical factors for successful introduction of solar units into immunization programs in the future including: •Sustainable financing mechanisms and incentives for health workers and technicians are in place to support long-term maintenance, repair, and replacement parts. •System design is carried out by qualified solar refrigerator professionals taking into account the conditions at installation sites. •Installation and repair are conducted by well-trained technicians. •Temperature performance is continuously monitored and protocols are in place to act on data that indicate problems. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

Experimental progress of a 4K VM/PT hybrid cryocooler for pre-cooling 1K sorption cooler

NASA Astrophysics Data System (ADS)

Pan, Changzhao; Zhang, Tong; Wang, Jue; Chen, Liubiao; Guo, Jia; Zhou, Yuan; Wang, Junjie

2017-12-01

Sub-kelvin refrigerator has many applications in space detector and manned space station, such as for the transition-edge superconducting (TES) bolometers operated in the 50 mK range. In order to meet the requirement of space applications, the high efficient, vibration free and high stability refrigerator need to be designed. VM/PT hybrid cryocooler is a new type cryocooler capable of attaining temperature below 4K. As a low frequency Stirling type cryocooler, it has the advantages of high stability and high efficiency. Combined with the vibration free sorption cooler and ADR refrigerator, a novel sub-kelvin cooling chain can be designed for the TES bolometer. This paper presents the recent experimental progress of the 4K VM/PT hybrid cryocooler in our laboratory. By optimizing of regenerators, phase shifters and heat exchangers, a lowest temperature of 2.6K was attained. Based on this cryocooler, a preliminary sorption cooler could be designed.

Low GWP Refrigerants Modelling Study for a Room Air Conditioner Having Microchannel Heat Exchangers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Bo; Bhandari, Mahabir S

Microchannel heat exchangers (MHX) have found great successes in residential and commercial air conditioning applications, being compact heat exchangers, to reduce refrigerant charge and material cost. This investigation aims to extend the application of MHXs in split, room air conditioners (RAC), per fundamental heat exchanger and system modelling. For this paper, microchannel condenser and evaporator models were developed, using a segment-to-segment modelling approach. The microchannel heat exchanger models were integrated to a system design model. The system model is able to predict the performance indices, such as cooling capacity, efficiency, sensible heat ratio, etc. Using the calibrated system and heatmore » exchanger models, we evaluated numerous low GWP (global warming potential) refrigerants. The predicted system performance indices, e.g. cooling efficiency, compressor discharge temperature, and required compressor displacement volume etc., are compared. Suitable replacements for R22 and R-410A for the room air conditioner application are recommended.« less

Food and medical sample freezer kit concept for Shuttle

NASA Technical Reports Server (NTRS)

Copeland, R. J.; Jaax, J. R.; Proctor, B. W.

1977-01-01

A variety of food and storage of samples can be provided by a Space Shuttle Orbiter Freezer Kit. The proposed concept is an integrated package consisting of four -23 C (-10 F) storage compartments and a Stirling cycle refrigeration unit. The Stirling cycle mechanical refrigeration was selected over alternative systems for superior efficiency and safety. The trade-offs and a conceptual design of the system are presented.

Impedance magnitude optimization of the regenerator in Stirling pulse tube cryocoolers working at liquid-helium temperatures

NASA Astrophysics Data System (ADS)

Cao, Q.; Qiu, L. M.; Zhi, X. Q.; Han, L.; Gan, Z. H.; Zhang, X. B.; Zhang, X. J.; Sun, D. M.

2013-12-01

The impedance magnitude is important for the design and operation of a Stirling pulse tube cryocooler (SPTC). However, the influence of the impedance magnitude on the SPTC working at liquid-helium temperatures is still not clear due to the complexity of refrigeration mechanism at this temperature range. In this study, the influence of the impedance magnitude on the viscous and thermal losses has been investigated, which contributes to the overall refrigeration efficiency. Different from the previous study at liquid nitrogen temperatures, it has been found and verified experimentally that a higher impedance magnitude may result in a larger mass flow rate accompanied with larger losses in the warmer region, hence the refrigeration efficiency is lowered. Numerical simulation is carried out in SPTCs of different geometry dimensions and working parameters, and the experimental study is carried out in a three-stage SPTC. A minimum no-load refrigeration temperature is achieved with an appropriate impedance magnitude that is determined by the combination of frequency and precooling temperature. A lowest temperature of 4.76 K is achieved at 28 Hz and a precooling temperature of 22.6 K, which is the lowest temperature ever achieved with He-4 for SPTCs. Impedance magnitude optimization is clearly an important consideration for the design of a 4 K SPTC.

77 FR 75428 - Decision and Order Granting a Waiver to Samsung From the Department of Energy Residential...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-20

... DEPARTMENT OF ENERGY Office of Energy Efficiency and Renewable Energy [Case No. RF-021] Decision... Refrigerator-Freezer Test Procedures AGENCY: Office of Energy Efficiency and Renewable Energy, Department of... Assistant Secretary for Energy Efficiency, Energy Efficiency and Renewable Energy. Decision and Order In the...

78 FR 53374 - Energy Conservation Program for Consumer Products: Test Procedures for Refrigerators...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-29

... Freezers AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy. ACTION: Extension... INFORMATION CONTACT: Mr. Lucas Adin, U.S. Department of Energy, Office of Energy Efficiency and Renewable... Energy Efficiency, Energy Efficiency and Renewable Energy. [FR Doc. 2013-21115 Filed 8-28-13; 8:45 am...

Active Magnetic Regenerative Liquefier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barclay, John A.; Oseen-Send, Kathryn; Ferguson, Luke

2016-01-12

This final report for the DOE Project entitled Active Magnetic Regenerative Liquefier (AMRL) funded under Grant DE-FG36-08GO18064 to Heracles Energy Corporation d.b.a. Prometheus Energy (Heracles/Prometheus) describes an active magnetic regenerative refrigerator (AMRR) prototype designed and built during the period from July 2008 through May 2011. The primary goal of this project was to make significant technical advances toward highly efficient liquefaction of hydrogen. Conventional hydrogen liquefiers at any scale have a maximum FOM of ~0.35 due primarily to the intrinsic difficulty of rapid, efficient compression of either hydrogen or helium working gases. Numerical simulation modeling of high performance AMRL designsmore » indicates certain designs have promise to increase thermodynamic efficiency from a FOM of ~0.35 toward ~0.5 to ~0.6. The technical approach was the use of solid magnetic working refrigerants cycled in and out of high magnetic fields to build an efficient active regenerative magnetic refrigeration module providing cooling power for AMRL. A single-stage reciprocating AMRR with a design temperature span from ~290 K to ~120 K was built and tested with dual magnetic regenerators moving in and out of the conductively-cooled superconducting magnet subsystem. The heat transfer fluid (helium) was coupled to the process stream (refrigeration/liquefaction load) via high performance heat exchangers. In order to maximize AMRR efficiency a helium bypass loop with adjustable flow was incorporated in the design because the thermal mass of magnetic refrigerants is higher in low magnetic field than in high magnetic field. Heracles/Prometheus designed experiments to measure AMRR performance under a variety of different operational parameters such as cycle frequency, magnetic field strength, heat transfer fluid flow rate, amount of bypass flow of the heat transfer fluid while measuring work input, temperature span, cooling capability as a function of cold temperature as a function of the amount of bypass flow of the heat transfer fluid. The operational AMRR prototype can be used to answer key questions such as the best recipe for multiple layers of different magnetic refrigerants in one or more integrated regenerators with varying amounts of bypass flow of the heat transfer fluid. Layered regenerators are necessary to span the AMRR range from 290 K to 120K. Our AMRR performance simulation model predicts that ~10-15 % of bypass flow should significantly improve the thermodynamic performance. Initial results obtained with regenerators made of gadolinium spheres were very encouraging; a temperature span of ~ 50 K (between 295K and 245 K) across both regenerators was achieved with zero bypass flow of the heat transfer fluid and with the magnetic field strength of ~4 T.« less

78 FR 41333 - Energy Efficiency Program for Commercial and Industrial Equipment: Public Meeting and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-10

.... EERE-2013-BT-STD-0022] RIN 1904-AD00 Energy Efficiency Program for Commercial and Industrial Equipment... the Framework Document pertaining to the development of energy conservation standards for refrigerated...

Conception of a test bench to generate known and controlled conditions of refrigerant mass flow.

PubMed

Martins, Erick F; Flesch, Carlos A; Flesch, Rodolfo C C; Borges, Maikon R

2011-07-01

Refrigerant compressor performance tests play an important role in the evaluation of the energy characteristics of the compressor, enabling an increase in the quality, reliability, and efficiency of these products. Due to the nonexistence of a refrigerating capacity standard, it is common to use previously conditioned compressors for the intercomparison and evaluation of the temporal drift of compressor performance test panels. However, there are some limitations regarding the use of these specific compressors as standards. This study proposes the development of a refrigerating capacity standard which consists of a mass flow meter and a variable-capacity compressor, whose speed is set based on the mass flow rate measured by the meter. From the results obtained in the tests carried out on a bench specifically developed for this purpose, it was possible to validate the concept of a capacity standard. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

Design, Project Execution, and Commissioning of the 1.8 K Superfluid Helium Refrigeration System for SRF Cryomodule Testing

DOE PAGES

Treite, P.; Nuesslein, U.; Jia, Yi; ...

2015-07-15

The Fermilab Cryomodule Test Facility (CMTF) provides a test bed to measure the performance of superconducting radiofrequency (SRF) cryomodules (CM). These SRF components form the basic building blocks of future high intensity accelerators such as the International Linear Collider (ILC) and a Muon Collider. Linde Kryotechnik AG and Linde Cryogenics have designed, constructed and commissioned the superfluid helium refrigerator needed to support SRF component testing at the CMTF Facility. The hybrid refrigerator is designed to operate in a variety of modes and under a wide range of boundary conditions down to 1.8 Kelvin set by CM design. Special features ofmore » the refrigerator include the use of warm and cold compression and high efficiency turbo expanders.This paper gives an overview on the wide range of the challenging cooling requirements, the design, fabrication and the commissioning of the installed cryogenic system.« less

Method using CO for extending the useful shelf-life of refrigerated red blood cells

DOEpatents

Bitensky, Mark W.

1995-01-01

Method using CO for extending the useful shelf-life of refrigerated red blood cells. Carbon monoxide is utilized for stabilizing hemoglobin in red blood cells to be stored at low temperature. Changes observed in the stored cells are similar to those found in normal red cell aging in the body, the extent thereof being directly related to the duration of refrigerated storage. Changes in cell buoyant density, vesiculation, and the tendency of stored cells to bind autologous IgG antibody directed against polymerized band 3 IgG, all of which are related to red blood cell senescence and increase with refrigerated storage time, have been substantially slowed when red blood cells are treated with CO. Removal of the carbon monoxide from the red blood cells is readily and efficiently accomplished by photolysis in the presence of oxygen so that the stored red blood cells may be safely transfused into a recipient.

Domestic refrigeration appliances in Poland: Potential for improving energy efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyers, S.; Schipper, L.; Lebot, B.

1993-08-01

This report is based on information collected from the main Polish manufacturer of refrigeration appliances. We describe their production facilities, and show that the energy consumption of their models for domestic sale is substantially higher than the average for similar models made in W. Europe. Lack of data and uncertainty about future production costs in Poland limits our evaluation of the cost-effective potential to increase energy efficiency, but it appears likely that considerable improvement would be economic from a societal perspective. Many design options are likely to have a simple payback of less than five years. We found that themore » production facilities are in need of substantial modernization in order to produce higher quality and more efficient appliances. We discuss policy options that could help to build a market for more efficient appliances in Poland and thereby encourage investment to produce such equipment.« less

Super-hydrophilic copper sulfide films as light absorbers for efficient solar steam generation under one sun illumination

NASA Astrophysics Data System (ADS)

Guo, Zhenzhen; Ming, Xin; Wang, Gang; Hou, Baofei; Liu, Xinghang; Mei, Tao; Li, Jinhua; Wang, Jianying; Wang, Xianbao

2018-02-01

Solar steam technology is one of the simplest, most direct and effective ways to harness solar energy through water evaporation. Here, we report the development using super-hydrophilic copper sulfide (CuS) films with double-layer structures as light absorbers for solar steam generation. In the double-layer structure system, a porous mixed cellulose ester (MCE) membrane is used as a supporting layer, which enables water to get into the CuS light absorbers through a capillary action to provide continuous water during solar steam generation. The super-hydrophilic property of the double-layer system (CuS/MCE) leads to a thinner water film close to the air-water interface where the surface temperature is sufficiently high, leading to more efficient evaporation (˜80 ± 2.5%) under one sun illumination. Furthermore, the evaporation efficiencies still keep a steady value after 15 cycles of testing. The super-hydrophilic CuS film is promising for practical application in water purification and evaporation as a light absorption material.

Salt pill design and fabrication for adiabatic demagnetization refrigerators

NASA Astrophysics Data System (ADS)

Shirron, Peter J.; McCammon, Dan

2014-07-01

The performance of an adiabatic demagnetization refrigerator (ADR) is critically dependent on the design and construction of the salt pills that produce cooling. In most cases, the primary goal is to obtain the largest cooling capacity at the low temperature end of the operating range. The realizable cooling capacity depends on a number of factors, including refrigerant mass, and how efficiently it absorbs heat from the various instrument loads. The design and optimization of “salt pills” for ADR systems depend not only on the mechanical, chemical and thermal properties of the refrigerant, but also on the range of heat fluxes that the salt pill must accommodate. Despite the fairly wide variety of refrigerants available, those used at very low temperature tend to be hydrated salts that require a dedicated thermal bus and must be hermetically sealed, while those used at higher temperature - greater than about 0.5 K - tend to be single- or poly-crystals that have much simpler requirements for thermal and mechanical packaging. This paper presents a summary of strategies and techniques for designing, optimizing and fabricating salt pills for both low- and mid-temperature applications.

Dynamic Characteristics of a Simple Brayton Cryocycle

NASA Astrophysics Data System (ADS)

Kutzschbach, A.; Kauschke, M.; Haberstroh, Ch.; Quack, H.

2006-04-01

The goal of the overall program is to develop a dynamic numerical model of helium refrigerators and the associated cooling systems based on commercial simulation software. The aim is to give system designers a tool to search for optimum control strategies during the construction phase of the refrigerator with the help of a plant "simulator". In a first step, a simple Brayton refrigerator has been investigated, which consists of a compressor, an after-cooler, a counter-current heat exchanger, a turboexpander and a heat source. Operating modes are "refrigeration" and "liquefaction". Whereas for the steady state design only component efficiencies are needed and mass and energy balances have to be calculated, for the dynamic calculation one needs also the thermal masses and the helium inventory. Transient mass and energy balances have to be formulated for many small elements and then solved simultaneously for all elements. Starting point of the simulation of the Brayton cycle is the steady state operation at design conditions. The response of the system to step and cyclic changes of the refrigeration or liquefaction rate are calculated and characterized.

The Development and Calculation of an Energy-saving Plant for Obtaining Water from Atmospheric Air

NASA Astrophysics Data System (ADS)

Uglanov, D. A.; Zheleznyak, K. E.; Chertykovsev, P. A.

2018-01-01

The article shows the calculation of characteristics of energy-efficient water generator from atmospheric air. This installation or the atmospheric water generator is the unique mechanism which produces safe drinking water by extraction it from air. The existing atmospheric generators allow to receive safe drinking water by means of process of condensation at air humidity at least equal to 35% and are capable to give to 25 liters of water in per day, and work from electricity. Authors offer to use instead of the condenser in the scheme of installation for increase volume of produced water by generator in per day, the following refrigerating machines: the vapor compression refrigerating machines (VCRM), the thermoelectric refrigerating machines (TRM) and the Stirling-cycle refrigerating machines (SRM). The paper describes calculation methods for each of refrigerating systems. Calculation of technical-and-economic indexes for the atmospheric water generator was carried out and the optimum system with the maximum volume of received water in per day was picked up. The atmospheric water generator which is considered in article will work from autonomous solar power station.

An experimental evaluation of two nonazeotropic refrigerant mixtures in a water-to-water breadboard heat pump

NASA Astrophysics Data System (ADS)

Kauffeld, Michael; Mulroy, William; McLinden, Mark; Didion, David

1990-02-01

As part of the Department of Energy/Oak Ridge National Laboratory Building Equipment Research program, the National Institute of Standards and Technology constructed an experimental, easily reconfigurable, water-to-water, breadboard heat pump apparatus in order to compare pure R22 to nonazeotropic refrigerant mixtures. Performance of the heat pump charged with a range of compositions of the binary mixtures R22/RI14 and R13/R12 were compared to R22. The advantage claimed for mixtures in this application is improved thermodynamic efficiency as a result of gliding refrigerant temperatures in the evaporator and condenser in low lift, high glide applications typical of air conditioning.

A small and light weight heat exchanger for on-board helium refrigerator

NASA Technical Reports Server (NTRS)

Koizumi, T.; Takahashi, M.; Uchida, T.; Kanazawa, Y.; Suzuki, M.

1983-01-01

A small and light weight heat exchanger used for small helium refrigerator has been developed by Sumitomo Heavy Industries, Ltd. This heat exchanger is a laminated metal heat exchanger which consists of perforated aluminum metal plates and glassfiber reinforced plastic separators. The size is from 100 mm to 28 mm in diameter and about 300 mm in length. The weight is from 2.5 kg to 0.6 kg. Also it can be used between room temperature and liquid helium temperature. The thermal efficiency obtained has been more than 96%. The heat exchanger has been practically used for on-board helium refrigerator in Japanese National Railways' superconducting magnetic levitated trains.

Smart Energy Cryo-refrigerator Technology for the next generation Very Large Array

NASA Astrophysics Data System (ADS)

Spagna, Stefano

2018-01-01

We describe a “smart energy” cryocooler technology architecture for the next generation Very Large Array that makes use of multiple variable frequency cold heads driven from a single variable speed air cooled compressor. Preliminary experiments indicate that the compressor variable flow control, advanced diagnostics, and the cryo-refrigerator low vibration, provide a unique energy efficient capability for the very large number of antennas that will be employed in this array.

The influence of pressure ratio on the regenerator performance

NASA Astrophysics Data System (ADS)

Lin, Y.; Zhu, S.

2017-12-01

For a multi-stage pulse tube refrigerator with displacer, improving the regenerator efficiency is important. A displacer can get higher operating pressure ratio compared with inertance tube. The pressure ratio and porosity influence on the regenerator performance with is discussed, and CFD simulation is done on a two-stage pulse tube refrigerator with displacer to show that mass flow rate and pressure wave relation in the regenerator can be realized by a step-displacer.

Estimation of performance of a J-T refrigerators operating with nitrogen-hydrocarbon mixtures and a coiled tubes-in-tube heat exchanger

NASA Astrophysics Data System (ADS)

Satya Meher, R.; Venkatarathnam, G.

2018-06-01

The exergy efficiency of Joule-Thomson (J-T) refrigerators operating with mixtures (MRC systems) strongly depends on the choice of refrigerant mixture and the performance of the heat exchanger used. Helically coiled, multiple tubes-in-tube heat exchangers with an effectiveness of over 96% are widely used in these types of systems. All the current studies focus only on the different heat transfer correlations and the uncertainty in predicting performance of the heat exchanger alone. The main focus of this work is to estimate the uncertainty in cooling capacity when the homogenous model is used by comparing the theoretical and experimental studies. The comparisons have been extended to some two-phase models present in the literature as well. Experiments have been carried out on a J-T refrigerator at a fixed heat load of 10 W with different nitrogen-hydrocarbon mixtures in the evaporator temperature range of 100-120 K. Different heat transfer models have been used to predict the temperature profiles as well as the cooling capacity of the refrigerator. The results show that the homogenous two-phase flow model is probably the most suitable model for rating the cooling capacity of a J-T refrigerator operating with nitrogen-hydrocarbon mixtures.

Performance characteristics of low global warming potential R134a alternative refrigerants in ejector-expansion refrigeration system

NASA Astrophysics Data System (ADS)

Mishra, Shubham; Sarkar, Jahar

2016-12-01

Performance assessment of ejector-expansion vapor compression refrigeration system with eco-friendly R134a alternative refrigerants (R152a, R1234yf, R600a, R600, R290, R161, R32, and propylene) is presented for air-conditioning application. Ejector has been modeled by considering experimental data based correlations of component efficiencies to take care of all irreversibilities. Ejector area ratio has been optimized based on maximum coefficient of performance (COP) for typical air-conditioner operating temperatures. Selected refrigerants have been compared based on area ratio, pressure lift ratio, entrainment ratio, COP, COP improvement and volumetric cooling capacity. Effects of normal boiling point and critical point on the performances have been studied as well. Using ejector as an expansion device, maximum improvement in COP is noted in R1234yf (10.1%), which reduces the COP deviation with R134a (4.5% less in basic cycle and 2.5% less in ejector cycle). Hence, R1234yf seems to be best alternative for ejector expansion system due to its mild flammability and comparable volumetric capacity and cooling COP. refrigerant R161 is superior to R134a in terms of both COP and volumetric cooling capacity, although may be restricted for low capacity application due to its flammability.

Simulated performance of biomass gasification based combined power and refrigeration plant for community scale application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chattopadhyay, S., E-mail: suman.mech09@gmail.com; Mondal, P., E-mail: mondal.pradip87@gmail.com; Ghosh, S., E-mail: sudipghosh.becollege@gmail.com

Thermal performance analysis and sizing of a biomass gasification based combined power and refrigeration plant (CPR) is reported in this study. The plant is capable of producing 100 kWe of electrical output while simultaneously producing a refrigeration effect, varying from 28-68 ton of refrigeration (TR). The topping gas turbine cycle is an indirectly heated all-air cycle. A combustor heat exchanger duplex (CHX) unit burns producer gas and transfer heat to air. This arrangement avoids complex gas cleaning requirements for the biomass-derived producer gas. The exhaust air of the topping GT is utilized to run a bottoming ammonia absorption refrigeration (AAR)more » cycle via a heat recovery steam generator (HRSG), steam produced in the HRSG supplying heat to the generator of the refrigeration cycle. Effects of major operating parameters like topping cycle pressure ratio (r{sub p}) and turbine inlet temperature (TIT) on the energetic performance of the plant are studied. Energetic performance of the plant is evaluated via energy efficiency, required biomass consumption and fuel energy savings ratio (FESR). The FESR calculation method is significant for indicating the savings in fuel of a combined power and process heat plant instead of separate plants for power and process heat. The study reveals that, topping cycle attains maximum power efficiency of 30%in pressure ratio range of 8-10. Up to a certain value of pressure ratio the required air flow rate through the GT unit decreases with increase in pressure ratio and then increases with further increase in pressure ratio. The capacity of refrigeration of the AAR unit initially decreases up to a certain value of topping GT cycle pressure ratio and then increases with further increase in pressure ratio. The FESR is found to be maximized at a pressure ratio of 9 (when TIT=1100°C), the maximum value being 53%. The FESR is higher for higher TIT. The heat exchanger sizing is also influenced by the topping cycle pressure ratio and GT-TIT.« less

Evaluation of Alternative Refrigerants for Mini-Split Air Conditioners

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelaziz, Omar; Shrestha, Som S

The phase-out of hydrochlorofluorocarbons (HCFC) refrigerants in developing countries is currently underway according to the Montreal Protocol. R-22 is one of the most commonly used HCFCs in the developing nations. It is extremely well suited for air conditioning and refrigeration (AC&R) in high ambient temperature environments. Non-Article 5 countries have already gone through the phase-out of HCFCs and settled on using R-410A as the refrigerant of choice for AC applications. Previous studies have shown that R-410A results in significant capacity and performance degradation at higher ambient temperature conditions. As such, there is a growing concern on finding alternative refrigerants tomore » R-22 that would have zero ODP, lower GWP, and at the same time maintain acceptable performance at higher ambient temperatures. Furthermore, the developed world s transition through higher global warming potential (GWP) refrigerants like HFC and HFC blends resulted in significant direct CO2 equivalent emissions. It is imperative to develop a bridge for developing nations to avoid the transition from HCFC to HFC and then from HFC to alternative lower GWP refrigerants. This paper summarizes data from an experimental campaign on alternative refrigerant evaluation for R-22 and R-410A substitutes for mini-split air conditioners designed for high ambient environments. The experimental evaluation was performed according to ANSI/ASHRAE Standard 37 and the performance was rated at test conditions specified by ANSI/AHRI 210-240 and ISO 5151. Additional tests were conducted at outdoor ambient temperatures of 52 C (125.6 F) and 55 C (131 F) to evaluate their performance at high ambient conditions. Alternative refrigerants, some of which are proprietary, included R-444B, DR-3, N-20b, ARM-20b, R-290, and DR-93 as alternatives to R-22 and R-32, DR-55, L41-2, ARM-71A, and HPR-2A as alternatives to R-410A. The units performances were first verified using the baseline refrigerant and then drop-in refrigerant evaluation followed including soft optimization to ensure refrigerant performance is adequately represented. The soft optimization included: 1) charge optimization, 2) lubricant change, and 3) flow control. The paper presents the relative performances (efficiency and capacity) of the alternative refrigerants compared to the baseline refrigerants at the different operating conditions. Paper concludes with remarks about the suitability of alternative refrigerants for R-22 and R-410A applications in high ambient temperature regions.« less

Improving the Efficiency and Effectiveness of Community Detection via Prior-Induced Equivalent Super-Network.

PubMed

Yang, Liang; Jin, Di; He, Dongxiao; Fu, Huazhu; Cao, Xiaochun; Fogelman-Soulie, Francoise

2017-03-29

Due to the importance of community structure in understanding network and a surge of interest aroused on community detectability, how to improve the community identification performance with pairwise prior information becomes a hot topic. However, most existing semi-supervised community detection algorithms only focus on improving the accuracy but ignore the impacts of priors on speeding detection. Besides, they always require to tune additional parameters and cannot guarantee pairwise constraints. To address these drawbacks, we propose a general, high-speed, effective and parameter-free semi-supervised community detection framework. By constructing the indivisible super-nodes according to the connected subgraph of the must-link constraints and by forming the weighted super-edge based on network topology and cannot-link constraints, our new framework transforms the original network into an equivalent but much smaller Super-Network. Super-Network perfectly ensures the must-link constraints and effectively encodes cannot-link constraints. Furthermore, the time complexity of super-network construction process is linear in the original network size, which makes it efficient. Meanwhile, since the constructed super-network is much smaller than the original one, any existing community detection algorithm is much faster when using our framework. Besides, the overall process will not introduce any additional parameters, making it more practical.

High-Performance Computing Data Center Water Usage Efficiency |

Science.gov Websites

cooler-an advanced dry cooler that uses refrigerant in a passive cycle to dissipate heat-was installed at efficiency-using wet cooling when it's hot and dry cooling when it's not. Learn more about NREL's partnership

Irreversible Brownian Heat Engine

NASA Astrophysics Data System (ADS)

Taye, Mesfin Asfaw

2017-10-01

We model a Brownian heat engine as a Brownian particle that hops in a periodic ratchet potential where the ratchet potential is coupled with a linearly decreasing background temperature. We show that the efficiency of such Brownian heat engine approaches the efficiency of endoreversible engine η =1-√{{Tc/Th}} [23]. On the other hand, the maximum power efficiency of the engine approaches η ^{MAX}=1-({Tc/Th})^{1\\over 4}. It is shown that the optimized efficiency always lies between the efficiency at quasistatic limit and the efficiency at maximum power while the efficiency at maximum power is always less than the optimized efficiency since the fast motion of the particle comes at the expense of the energy cost. If the heat exchange at the boundary of the heat baths is included, we show that such a Brownian heat engine has a higher performance when acting as a refrigerator than when operating as a device subjected to a piecewise constant temperature. The role of time on the performance of the motor is also explored via numerical simulations. Our numerical results depict that the time t and the external load dictate the direction of the particle velocity. Moreover, the performance of the heat engine improves with time. At large t (steady state), the velocity, the efficiency and the coefficient of performance of the refrigerator attain their maximum value. Furthermore, we study the effect of temperature by considering a viscous friction that decreases exponentially as the background temperature increases. Our result depicts that the Brownian particle exhibits a fast unidirectional motion when the viscous friction is temperature dependent than that of constant viscous friction. Moreover, the efficiency of this motor is considerably enhanced when the viscous friction is temperature dependent. On the hand, the motor exhibits a higher performance of the refrigerator when the viscous friction is taken to be constant.

Scaling and Optimization of Magnetic Refrigeration for Commercial Building HVAC Systems Greater than 175 kW in Capacity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelaziz, Omar; West, David L; Mallow, Anne M

Heating, ventilation, air-conditioning and refrigeration (HVACR) account for approximately one- third of building energy consumption. Magnetic refrigeration presents an opportunity for significant energy savings and emissions reduction for serving the building heating, cooling, and refrigeration loads. In this paper, we have examined the magnet and MCE material requirements for scaling magnetic refrigeration systems for commercial building cooling applications. Scaling relationships governing the resources required for magnetic refrigeration systems have been developed. As system refrigeration capacity increases, the use of superconducting magnet systems becomes more applicable, and a comparison is presented of system requirements for permanent and superconducting (SC) magnetization systems.more » Included in this analysis is an investigation of the ability of superconducting magnet based systems to overcome the parasitic power penalty of the cryocooler used to keep SC windings at cryogenic temperatures. Scaling relationships were used to develop the initial specification for a SC magnet-based active magnetic regeneration (AMR) system. An optimized superconducting magnet was designed to support this system. In this analysis, we show that the SC magnet system consisting of two 0.38 m3 regenerators is capable of producing 285 kW of cooling power with a T of 28 K. A system COP of 4.02 including cryocooler and fan losses which illustrates that an SC magnet-based system can operate with efficiency comparable to traditional systems and deliver large cooling powers of 285.4 kW (81.2 Tons).« less

77 FR 49443 - Decision and Order Granting a Waiver to Sanyo From the Department of Energy Residential...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-16

... DEPARTMENT OF ENERGY Office of Energy Efficiency and Renewable Energy [Case No. RF-022] Decision... Refrigerator-Freezer Test Procedures AGENCY: Office of Energy Efficiency and Renewable Energy, Department of... characteristics. The Assistant Secretary for Energy Efficiency and Renewable Energy (the Assistant Secretary) may...

Waste heat driven absorption refrigeration process and system

DOEpatents

Wilkinson, William H.

1982-01-01

Absorption cycle refrigeration processes and systems are provided which are driven by the sensible waste heat available from industrial processes and other sources. Systems are disclosed which provide a chilled water output which can be used for comfort conditioning or the like which utilize heat from sensible waste heat sources at temperatures of less than 170.degree. F. Countercurrent flow equipment is also provided to increase the efficiency of the systems and increase the utilization of available heat.

Design and Operation of a 4kW Linear Motor Driven Pulse Tube Cryocooler

NASA Astrophysics Data System (ADS)

Zia, J. H.

2004-06-01

A 4 kW electrical input Linear Motor driven pulse tube cryocooler has successfully been designed, built and tested. The optimum operation frequency is 60 Hz with a design refrigeration of >200 W at 80 K. The design exercise involved modeling and optimization in DeltaE software. Load matching between the cold head and linear motor was achieved by careful sizing of the transfer tube. The cryocooler makes use of a dual orifice inertance network and a single compliance tank for phase optimization and streaming suppression in the pulse tube. The in-line cold head design is modular in structure for convenient change-out and re-assembly of various components. The Regenerator consists of layers of two different grades of wire-mesh. The Linear motor is a clearance seal, dual opposed piston design from CFIC Inc. Initial results have demonstrated the refrigeration target of 200 W by liquefying Nitrogen from an ambient temperature and pressure. Overall Carnot efficiencies of 13% have been achieved and efforts to further improve efficiencies are underway. Linear motor efficiencies up to 84% have been observed. Experimental results have shown satisfactory compliance with model predictions, although the effects of streaming were not part of the model. Refrigeration loss due to streaming was minimal at the design operating conditions of 80 K.

Energy Choices for Consumers

ERIC Educational Resources Information Center

Nolan, William T.

1977-01-01

Sample problems concerning energy consumption and conservation with air conditioners, electric ranges, refrigerators and televisions are provided. The energy efficiency ratio (EER) is also discussed. (CP)

Performance Optimization of Alternative Lower Global Warming Potential Refrigerants in Mini-Split Room Air Conditioners

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, Bo; Abdelaziz, Omar; Shrestha, Som S

Oak Ridge National laboratory (ORNL) recently conducted extensive laboratory, drop-in investigations for lower Global Warming Potential (GWP) refrigerants to replace R-22 and R-410A. ORNL studied propane, DR-3, ARM-20B, N-20B and R-444B as lower GWP refrigerant replacement for R-22 in a mini-split room air conditioner (RAC) originally designed for R-22; and, R-32, DR-55, ARM-71A, and L41-2, in a mini-split RAC designed for R-410A. We obtained laboratory testing results with very good energy balance and nominal measurement uncertainty. Drop-in studies are not enough to judge the overall performance of the alternative refrigerants since their thermodynamic and transport properties might favor different heatmore » exchanger configurations, e.g. cross-flow, counter flow, etc. This study compares optimized performances of individual refrigerants using a physics-based system model tools. The DOE/ORNL Heat Pump Design Model (HPDM) was used to model the mini-split RACs by inputting detailed heat exchangers geometries, compressor displacement and efficiencies as well as other relevant system components. The RAC models were calibrated against the lab data for each individual refrigerant. The calibrated models were then used to conduct a design optimization for the cooling performance by varying the compressor displacement to match the required capacity, and changing the number of circuits, refrigerant flow direction, tube diameters, air flow rates in the condenser and evaporator at 100% and 50% cooling capacities. This paper compares the optimized performance results for all alternative refrigerants and highlights best candidates for R-22 and R-410A replacement.« less

Active magnetic regenerator

DOEpatents

Barclay, J.A.; Steyert, W.A.

1981-01-27

An apparatus and method for refrigeration are disclosed which provides efficient refrigeration over temperature ranges in excess of 20/sup 0/C and which requires no maintenance and is, therefore, usable on an unmanned satellite. The apparatus comprises a superconducting magnet which may be solenoidal. A piston comprising a substance such as a rare earth substance which is maintained near its Curie temperature reciprocates through the bore of the solenoidal magnet. A magnetic drive rod is connected to the piston and appropriate heat sinks are connected thereto. The piston is driven by a suitable mechanical drive such as an electric motor and cam. In practicing the invention, the body of the piston is magnetized and demagnetized as it moves through the magnetic field of the solenoid to approximate any of the following cycles or a condition thereof as well as, potentially, other cycles: Brayton, Carnot, Ericsson, and Stirling. Advantages of the present invention include: that refrigeration can be accomplished over at least a 20/sup 0/C scale at superconducting temperatures as well as at more conventional temperatures; very high efficiency, high reliability, and small size. (LCL)

A multi-stage traveling-wave thermoacoustically-driven refrigeration system operating at liquefied natural gas temperature

NASA Astrophysics Data System (ADS)

Luo, K.; Sun, D. M.; Zhang, J.; Shen, Q.; Zhang, N.

2017-12-01

This study proposes a multi-stage travelling-wave thermoacoustically refrigeration system (TAD-RS) operating at liquefied natural gas temperature, which consists of two thermoacoustic engines (TAE) and one thermoacoustic refrigerator (TAR) in a closed-loop configuration. Three thermoacoustic units connect each other through a resonance tube of small cross-sectional area, achieving “self-matching” for efficient thermoacoustic conversion. Based on the linear thermoacoustic theory, a model of the proposed system has been built by using DeltaEC program to show the acoustic field characteristics and performance. It is shown that with pressurized 5 MPa helium as working gas, the TAEs are able to build a stable and strong acoustic field with a frequency of about 85 Hz. When hot end temperature reaches 923 K, this system can provide about 1410 W cooling power at 110 K with an overall exergy efficiency of 15.5%. This study indicates a great application prospect of TAD-RS in the field of natural gas liquefaction with a large cooling capacity and simple structure.

The influence of granulation on super disintegrant performance.

PubMed

Zhao, Na; Augsburger, Larry L

2006-02-01

The purpose of this study is to identify the causes of efficiency loss of super disintegrants following granulation or reworking. Two processes, precompression and prewetting, were proposed to simulate the processes during dry and wet granulation, respectively. The disintegration efficiency of the resulting disintegrant granules was tested in model formulations composed of dicalcium phosphate and lactose with the unprocessed disintegrants as controls. No significant difference was shown in the intrinsic swelling and the water uptake abilities of all super disintegrants following dry granulation. However, a significant decrease was observed for both Primojel and Polyplasdone XL10 in the rate of water being absorbed into the tablet matrix following wet granulation, but not for Ac-Di-Sol. United States Pharmacopeia (USP) disintegration testing without disc revealed a significant increase in disintegration time for tablets formulated with dry granulated Primojel and Polyplasdone XL10 and all wet granulated disintegrants. The increase in particle size following granulation appears to be the cause of the loss in disintegration efficiency. In conclusion, Ac-Di-Sol is less affected by both precompression and prewetting. The efficiency of Primojel and Polyplasdone XL10 is highly dependent on their particle size. Descreasing the particle size tends to increase their efficiency. Due to the size increase following granulation, a higher addition level of super disintegrant is required to ensure fast and uniform disintegration of tablets prepared by granulation.

The Liquid Nitrogen System for Chamber A: A Change from Original Forced Flow Design to a Natural Flow (Thermo Siphon) System

NASA Technical Reports Server (NTRS)

Homan, Jonathan; Montz, Michael; Sidi-Yekhlef, Ahmed; Ganni, Venkatarao (Rao); Knudsen, Peter; Garcia, Sam; Linza, Robert; Meagher, Daniel; Lauterbauch, John

2008-01-01

NASA Johnson Space Center (JSC) in Houston is currently supplementing its 20K helium refrigeration system to meet the new requirements for testing the James Web Space Telescope in the environmental control Chamber-A (65 dia x 120 high) in Building 32. The new system is required to meet the various operating modes which include a high 20K heat load, a required temperature stability at the load, rapid (but controlled) cool down and warm up and bake out of the chamber. This paper will present the proposed modifications to the existing helium system(s) to incorporate the new requirements and the integration of the new helium refrigerator with the existing two 3.5KW 20K helium refrigerators. In addition, the floating pressure process control philosophy to achieve high efficiency over the operating range (40% to 100% of the refrigeration system capacity), and the required temperature stability of +/- 0.25 K at the load will be discussed. The refrigeration systems ability to naturally seek the operating conditions under various loads and thus minimizing operator involvement and the over all improvements to the system operability and the reliability will be explained.

A novel solar bi-ejector refrigeration system and the performance of the added injector with different structures and operation parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Fei; Shen, Shengqiang

2009-12-15

A novel solar bi-ejector refrigeration system was investigated, whose difference compared to the traditional system is that the circulation pump is replaced by a thermal injector. The new system works more stably and needs less maintenance work than the old one, and the whole system can more fully utilize the solar energy. The mathematical models for calculating the performance of the injector and the whole solar refrigeration system were established. The pressure rise performance of injector under different structure and operation parameters and the performance of solar bi-ejector refrigeration system were studied with R123. The results show that the dischargedmore » pressure of injector is affected by structure dimensions of injector and operation conditions. With increasing generation temperature, the entrainment ratio of ejector becomes better while that of injector becomes worse and the overall thermal efficiency of the solar bi-ejector refrigeration system first increases and then decreases with an optimum value of 0.132 at generation temperature of 105 C, condensation temperature of 35 C and evaporation temperature of 10 C. (author)« less

Salt Pill Design and Fabrication for Adiabatic Demagnetization Refrigerators

NASA Technical Reports Server (NTRS)

Shirron, Peter J.; Mccammon, Dan

2014-01-01

The performance of an adiabatic demagnetization refrigerator (ADR) is critically dependent on the design and construction of the salt pills that produce cooling. In most cases, the primary goal is to obtain the largest cooling capacity at the low temperature end of the operating range. The realizable cooling capacity depends on a number of factors, including refrigerant mass, and how efficiently it absorbs heat from the various instrument loads. The design and optimization of "salt pills" for ADR systems depend not only on the mechanical, chemical and thermal properties of the refrigerant, but also on the range of heat fluxes that the salt pill must accommodate. Despite the fairly wide variety of refrigerants available, those used at very low temperature tend to be hydrated salts that require a dedicated thermal bus and must be hermetically sealed, while those used at higher temperature - greater than about 0.5 K - tend to be single-­- or poly-­-crystals that have much simpler requirements for thermal and mechanical packaging. This paper presents a summary of strategies and techniques for designing, optimizing and fabricating salt pills for both low-­- and mid-­-temperature applications.

Comparison of two models of a double inlet miniature pulse tube refrigerator: Part B electrical analogy

NASA Astrophysics Data System (ADS)

Bailly, Yannick; Nika, Philippe

2002-10-01

The design of a double inlet pulse tube refrigerator is investigated by means of an analogy with an electric circuit. The results obtained are compared with both those of the thermodynamic model (Part A) and experiments. The basic formulation of equivalent electronic components is discussed and a few improvements are proposed for adjusting the theoretical expressions of the electric impedance concerning the capillaries and the regenerator. Then additional effects such as pressure drops due to geometrical singularities are taken into account considering the different internal flow regimes that may occur. Besides a simplified formulation for the regenerator efficiency is deduced from considerations on its harmonic functioning. In this analysis, the emphasis concerns principally the design of miniature cryocoolers dedicated to electronic applications. Those models are applied to a commercial miniature refrigerator. A discussion of their relevance is achieved and a few suggestions on the refrigerator design are proposed in order to improve the cooling production.

Conceptual design and exergy analysis of an integrated structure of natural gas liquefaction and production of liquid fuels from natural gas using Fischer-Tropsch synthesis

NASA Astrophysics Data System (ADS)

Niasar, Malek Shariati; Amidpour, Majid

2018-01-01

In this paper, utilizing absorption refrigeration system as an alternative to compression refrigeration system of MFC refrigeration cycle in an integrated superstructure with the main aim of reduction in required energy is investigated. High-energy consumption in such units is reduced because of the removal of a stage of the compression system, while the possibility of using waste energy through employing of absorption refrigeration system can be provided. A superstructure including cogeneration of heating, cooling and power for LNG production and liquid fuels using Fischer-Tropsch synthesis are investigated. Exergy analysis shows that the greatest amount of exergy destruction of equipment is related to the compressors by 28.99% and the lowest exergy destruction is related to the gas turbine by 0.17%. Integrated structure has overall thermal efficiency of 90% and specific power of 0.1988 kW h/(kg LNG)-1.

Method using CO for extending the useful shelf-life of refrigerated red blood cells

DOEpatents

Bitensky, M.W.

1995-12-19

A method is disclosed using CO for extending the useful shelf-life of refrigerated red blood cells. Carbon monoxide is utilized for stabilizing hemoglobin in red blood cells to be stored at low temperature. Changes observed in the stored cells are similar to those found in normal red cell aging in the body, the extent thereof being directly related to the duration of refrigerated storage. Changes in cell buoyant density, vesiculation, and the tendency of stored cells to bind autologous IgG antibody directed against polymerized band 3 IgG, all of which are related to red blood cell senescence and increase with refrigerated storage time, have been substantially slowed when red blood cells are treated with CO. Removal of the carbon monoxide from the red blood cells is readily and efficiently accomplished by photolysis in the presence of oxygen so that the stored red blood cells may be safely transfused into a recipient. 5 figs.

Intermittent Solar Ammonia Absorption Cycle (ISAAC) refrigeration for lesser developed countries

NASA Astrophysics Data System (ADS)

Erickson, Donald C.

1990-02-01

The Intermittent Solar Ammonia Absorption Cycle (ISAAC) refrigerator is a solar thermal technology which provides low cost, efficient, reliable ice-making to areas without ready access to electricity. An ISAAC refrigeration system consists of a compound parabolic solar collector, two pressure vessels, a condenser, a cold box or refrigerated space, and simple connective piping -- no moving parts or electrical components. Most parts are simple construction or plumbing grade materials, locally available in many remote areas. This technology has numerous potential benefits in lesser developed countries both by providing a cheap, reliable source of ice, and, since manufacture requires only semi-skilled labor, a source of employment to the local economy. Applications include vaccine storage for health care clinics; fish, meat, and dairy product storage; and personal consumption. Importantly, this technology increases the quality of life for people in lesser developed countries without depleting fossil fuel resources or increasing the release of greenhouse gases such as CO2 and chlorofluorocarbons.

TEWI Evaluation for Refrigeration and Air-Conditioning Systems in Office Buildings with Different Regional Heat Demand

NASA Astrophysics Data System (ADS)

Sobue, Atsushi; Watanabe, Koichi

In the present study, we quantitatively evaluated the global warming impact by refrigeration and air-conditioning systems in office buildings on the basis of reliable TEWI information. This paper proposes an improved TEWI evaluation procedure by considering regional heat demands and part load of air-conditioning systems. In the TEWI evaluation of commercial chillers, a percentage of the impact by refrigerant released to the atmosphere (direct effect) is less than 19.9% in TEWI values. Therefore, a reduction of the impact by CO2 released as a result of the energy consumed to drive the refrigeration or air-conditioning systems through out their lifetime (indirect effect) is the most effective measure in reducing the global warming impact. On the other hand, we have also pointed out energy loss that might be generated by an excess investment to the equipment. We have also showed a usefulness in dividing the heating / cooling system into several small-capacity units so as to improve the energy utilization efficiency.

The distinguishing signature of Magnetic Penrose Process

NASA Astrophysics Data System (ADS)

Dadhich, Naresh; Tursunov, Arman; Ahmedov, Bobomurat; Stuchlík, Zdeněk

2018-04-01

In this Letter, we wish to point out that the distinguishing feature of Magnetic Penrose process (MPP) is its super high efficiency exceeding 100% (which was established in mid 1980s for discrete particle accretion) of extraction of rotational energy of a rotating black hole electromagnetically for a magnetic field of milli Gauss order. Another similar process, which is also driven by electromagnetic field, is Blandford-Znajek mechanism (BZ), which could be envisaged as high magnetic field limit MPP as it requires threshold magnetic field of order 104G. Recent simulation studies of fully relativistic magnetohydrodynamic flows have borne out super high efficiency signature of the process for high magnetic field regime; viz BZ. We would like to make a clear prediction that similar simulation studies of MHD flows for low magnetic field regime, where BZ would be inoperative, would also have super efficiency.

Basic aspects and contributions to the optimization of energy systems exploitation of a super tanker ship

NASA Astrophysics Data System (ADS)

Faitar, C.; Novac, I.

2017-08-01

Today, the concept of energy efficiency or energy optimization in ships has become one of the main problems of engineers in the whole world. To increase the fiability of a crude oil super tanker ship it means, among other things, to improve the energy performance and optimize the fuel consumption of ship through the development of engines and propulsion system or using alternative energies. Also, the importance of having an effective and reliable Power Management System (PMS) in a vessel operating system means to reduce operational costs and maintain power system of machine parts working in minimum stress in all operating conditions. Studying the Energy Efficiency Design Index and Energy Efficiency Operational Indicator for a crude oil super tanker ship, it allows us to study the reconfiguration of ship power system introducing new generation systems.

Space Station Freedom food management

NASA Technical Reports Server (NTRS)

Whitehurst, Troy N., Jr.; Bourland, Charles T.

1992-01-01

This paper summarizes the specification requirements for the Space Station Food System, and describes the system that is being designed and developed to meet those requirements. Space Station Freedom will provide a mix of frozen, refrigerated, rehydratable, and shelf stable foods. The crew will pre-select preferred foods from an approved list, to the extent that proper nutrition balance is maintained. A galley with freezers, refrigerators, trash compactor, and combination microwave and convection ovens will improve crew efficiency and productivity during the long Space Station Freedom (SSF) missions.

Retail Building Guide for Entrance Energy Efficiency Measures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stein, J.; Kung, F.

2012-03-01

This booklet is based on the findings of an infiltration analysis for supermarkets and large retail buildings without refrigerated cases. It enables retail building managers and engineers to calculate the energy savings potential for vestibule additions for supermarkets; and bay door operation changes in large retail stores without refrigerated cases. Retail managers can use initial estimates to decide whether to engage vendors or contractors of vestibules for pricing or site-specific analyses, or to decide whether to test bay door operation changes in pilot stores, respectively.

Design of Standards and Labeling programs in Chile: Techno-Economic Analysis for Refrigerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Letschert, Virginie E.; McNeil, Michael A.; Pavon, Mariana

2013-05-01

Lawrence Berkeley National Laboratory is a global leader in the study of energy efficiency and its effective implementation through government policy. The Energy Analysis and Environmental Impacts Department of LBNL’s Environmental Energy Technologies Division provides technical assistance to help federal, stat e and local government agencies in the United States, and throughout the world, develop long-term strategies, policy, and programs to encourage energy efficiency in all sectors and industries. In the past, LBNL has assisted staff of various countries government agencies and their con tractors in providing methodologies to analyze cost-effectiveness of regulations and asses s overall national impacts ofmore » efficiency programs. The paper presents the work done in collaboration with the Ministry of Energy (MoE) in Chile and the Collaborative Labeling Appliance Standards Programs (CLASP) on designing a Minimum Energy Performance Standards (MEPS) and ext ending the current labeling program for refrigerators.« less

Tests of a 2-Stage, Axial-Flow, 2-Phase Turbine

NASA Technical Reports Server (NTRS)

Elliott, D. G.

1982-01-01

A two phase flow turbine with two stages of axial flow impulse rotors was tested with three different working fluid mixtures at a shaft power of 30 kW. The turbine efficiency was 0.55 with nitrogen and water of 0.02 quality and 94 m/s velocity, 0.57 with Refrigerant 22 of 0.27 quality and 123 m/s velocity, and 0.30 with steam and water of 0.27 quality and 457 m/s velocity. The efficiencies with nitrogen and water and Refrigerant 22 were 86 percent of theoretical. At that fraction of theoretical, the efficiencies of optimized two phase turbines would be in the low 60 percent range with organic working fluids and in the mid 50 percent range with steam and water. The recommended turbine design is a two stage axial flow impulse turbine followed by a rotary separator for discharge of separate liquid and gas streams and recovery of liquid pressure.

Energy and cost analysis of residential refrigerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoskins, R.A.; Hirst, E.

1977-01-01

A detailed computer model is developed to calculate energy flows and electricity use for residential refrigerators. Model equations are derived from applications of the first law of thermodynamics, analysis of manufacturers' literature, and related studies. The model is used to evaluate the energy (and associated initial cost) impacts of alternative designs to reduce refrigerator energy use. Model results show that 56 percent of the total heat gain in a typical 0.45 m/sup 3/ (16 ft/sup 3/) top-freezer refrigerator is due to conduction through cabinet walls and doors. The remaining 44 percent is from door openings, heaters, fans, food, gasket areamore » infiltration, and miscellaneous heat sources. Operation of the compressor to remove this heat and maintain the refrigerated spaces at constant temperatures accounts for 70 percent of the unit's electricity use. The remainder is for operation of heaters and fans. Several energy-saving design changes are examined using the energy model. These changes are: increased insulation thickness, improved insulation conductivity, removal of fan from cooled area, use of anti-sweat heater switch, improved compressor efficiency, increased condenser and evaporator surface areas, and elimination of the frost-free feature. Application of all these changes would reduce refrigerator electricity use 71 percent and increase initial cost 5 percent. Implementing all these changes except for elimination of the frost-free feature would reduce electricity use 52 percent and increase initial cost 19 percent. These results show that there are large opportunities for reducing refrigerator electricity use with only slight initial cost increases.« less

Characteristics of stallion epididymal spermatozoa at collection and effect of two refrigeration protocols on the quality of the frozen/thawed sperm cells.

PubMed

Guimarães, T; Lopes, G; Ferreira, P; Leal, I; Rocha, A

2012-12-01

Cryopreservation of epididymal spermatozoa is a useful tool to preserve genetic material of valuable stallions after emergency castration or unexpected death. For that, testicles and epididymides are generally sent refrigerated to the laboratory. Collection of epididymal spermatozoa is a simple procedure that reduces the volume of the material to be shipped, and may improve the quality of the chilled epididymal sperm cells. In the present study we compared the characteristics of frozen/thawed epididymal spermatozoa after refrigeration of the epididymis or after direct refrigeration of the extended epididymal sperm cells. Ejaculated sperm samples were obtained from 10 healthy stallions with at least 15 days of sexual rest, before routine orchiectomies. Spermatozoa were recovered from the epididymal tail immediately after castration (EPI), after refrigeration of the epididymis for 24h at 4°C (EPI R) and recovered from epididymal tail immediately after castration and stored for 24h at 4°C (EPI RR). Total motility, straight-line velocity, percentage of rapid cells, viability and morphological defects were similar (p>0.05) among different treatments, and post-thaw viability was higher (p<0.05) in EPI than in the ejaculated sperm. The similarity of post-thaw parameters led us to conclude that immediate collection and refrigeration of the epididymal sperm cells or refrigeration of the whole epididymis are equally efficient as a means of transporting material for 24h before cryopreservation of epididymal spermatozoa. Copyright © 2012 Elsevier B.V. All rights reserved.

Experimental investigation of an ammonia-based combined power and cooling cycle

NASA Astrophysics Data System (ADS)

Tamm, Gunnar Olavi

A novel ammonia-water thermodynamic cycle, capable of producing both power and refrigeration, was proposed by D. Yogi Goswami. The binary mixture exhibits variable boiling temperatures during the boiling process, which leads to a good thermal match between the heating fluid and working fluid for efficient heat source utilization. The cycle can be driven by low temperature sources such as solar, geothermal, and waste heat from a conventional power cycle, reducing the reliance on high temperature sources such as fossil fuels. A theoretical simulation of the cycle at heat source temperatures obtainable from low and mid temperature solar collectors showed that the ideal cycle could produce power and refrigeration at a maximum exergy efficiency, defined as the ratio of the net work and refrigeration output to the change in availability of the heat source, of over 60%. The exergy efficiency is a useful measure of the cycle's performance as it compares the effectiveness of different cycles in harnessing the same source. An experimental system was constructed to demonstrate the feasibility of the cycle and to compare the experimental results with the theoretical simulations. In this first phase of experimentation, the turbine expansion was simulated with a throttling valve and a heat exchanger. Results showed that the vapor generation and absorption condensation processes work experimentally. The potential for combined turbine work and refrigeration output was evidenced in operating the system. Analysis of losses led to modifications in the system design, which were implemented to yield improvements in heat exchange, vapor generation, pump performance and overall stability. The research that has been conducted verifies the potential of the power and cooling cycle as an alternative to using conventional fossil fuel technologies. The research that continues is to further demonstrate the concept and direct it towards industry. On the large scale, the cycle can be used for industrial power production or as a central power plant for a community, with refrigeration produced as required by the application. On the small scale, an affordable residential or commercial unit could allow independent electricity generation for the home or business while also cooling it.

Fast and efficient molecule detection in localization-based super-resolution microscopy by parallel adaptive histogram equalization.

PubMed

Li, Yiming; Ishitsuka, Yuji; Hedde, Per Niklas; Nienhaus, G Ulrich

2013-06-25

In localization-based super-resolution microscopy, individual fluorescent markers are stochastically photoactivated and subsequently localized within a series of camera frames, yielding a final image with a resolution far beyond the diffraction limit. Yet, before localization can be performed, the subregions within the frames where the individual molecules are present have to be identified-oftentimes in the presence of high background. In this work, we address the importance of reliable molecule identification for the quality of the final reconstructed super-resolution image. We present a fast and robust algorithm (a-livePALM) that vastly improves the molecule detection efficiency while minimizing false assignments that can lead to image artifacts.

Design of an adiabatic demagnetization refrigerator for studies in astrophysics

NASA Technical Reports Server (NTRS)

Castles, S.

1983-01-01

An adiabatic demagnetization refrigerator was designed for cooling infrared bolometers for studies in astrophysics and aeronomy. The design was tailored to the requirements of a Shuttle sortie experiment. The refrigerator should be capable of maintaining three bolometers at 0.1 K with a 90% cycle. The advantage are of operations the bolometer at 0.1K. greater sensitivity, faster response time, and the ability to use larger bolometer elements without compromising the response time. The design presented is the first complete design of an ADR intended for use in space. The most important of these specifications are to survive a Shuttle launch, to operate with 1.5 K - 2.0 K space-pumped liquid helium as a heat sink, to have a 90% duty cycle, and to be highly efficient.

High Efficiency Thermoelectric Materials and Devices

NASA Technical Reports Server (NTRS)

Kochergin, Vladimir (Inventor)

2013-01-01

Growth of thermoelectric materials in the form of quantum well super-lattices on three-dimensionally structured substrates provide the means to achieve high conversion efficiency of the thermoelectric module combined with inexpensiveness of fabrication and compatibility with large scale production. Thermoelectric devices utilizing thermoelectric materials in the form of quantum well semiconductor super-lattices grown on three-dimensionally structured substrates provide improved thermoelectric characteristics that can be used for power generation, cooling and other applications..

High-Efficiency Helical Coil Electromagnetic Launcher and High Power Hall-Effect Switch

DTIC Science & Technology

2008-02-29

also given that demonstrate significant launcher performance benefits by super-cooling the armature (i.e., using liquid nitrogen ). 14. ABSTRACT... liquid nitrogen temperatures). A computer model for a magnetically-controlled Hall-effect switch is developed. The model is constructed in the PSpice...of super-cooling is demonstrated with liquid nitrogen cooling and indicates super-cooled EML operation is desirable if cryo-cooling is practical for

Possibility of using adsorption refrigeration unit in district heating network

NASA Astrophysics Data System (ADS)

Grzebielec, Andrzej; Rusowicz, Artur; Jaworski, Maciej; Laskowski, Rafał

2015-09-01

Adsorption refrigeration systems are able to work with heat sources of temperature starting with 50 °C. The aim of the article is to determine whether in terms of technical and economic issues adsorption refrigeration equipment can work as elements that produce cold using hot water from the district heating network. For this purpose, examined was the work of the adsorption air conditioning equipment cooperating with drycooler, and the opportunities offered by the district heating network in Warsaw during the summer. It turns out that the efficiency of the adsorption device from the economic perspective is not sufficient for production of cold even during the transitional period. The main problem is not the low temperature of the water supply, but the large difference between the coefficients of performance, COPs, of adsorption device and a traditional compressor air conditioning unit. When outside air temperature is 25 °C, the COP of the compressor type reaches a value of 4.49, whereas that of the adsorption device in the same conditions is 0.14. The ratio of the COPs is 32. At the same time ratio between the price of 1 kWh of electric power and 1 kWh of heat is only 2.85. Adsorption refrigeration equipment to be able to compete with compressor devices, should feature COPads efficiency to be greater than 1.52. At such a low driving temperature and even changing the drycooler into the evaporative cooler it is not currently possible to achieve.

Adiabatic Demagnetisation Refrigerators for Future Sub-Millimetre Space Missions

NASA Astrophysics Data System (ADS)

Hepburn, I. D.; Davenport, I.; Smith, A.

1995-10-01

Space worthy refrigeration capable of providing a 100 mK and below heat load sink for bolometric detectors will be required for the next generation of sub-millimetre space missions. Adiabatic demagnetisation refrigeration (ADR), being a gravity independent laboratory method for obtaining such temperatures, is a favourable technique for utilisation in space. We show that by considering a 3 salt pill refrigerator rather than the classic single salt pill design the space prohibitive laboratory ADR properties of high magnetic field (6 Tesla) and a<2 K environment (provided by a bath of liquid4He) can be alleviated, while maintaining a sufficient low temperature hold time and short recycle time. The additional salt pills, composed of Gadolinium Gallium Garnet (GGG) provide intermediate cooling stages, enabling operation from a 4 K environment provided by a single 4 K mechanical cooler, thereby providing consumable free operation. Such ADRs could operate with fields as low as 1 Tesla allowing the use of high temperature, mechanically cooled superconducting magnets and so effectively remove the risk of quenching. We discuss the possibility of increasing the hold time from 3 hours, for the model presented, to between 40 and 80 hours, plus reducing the number of salt pills to two, through the use of a more efficient Garnet. We believe the technical advances necessitated by the envisaged ADRs are minimal and conclude that such ADRs offer a long orbital life time, consumable free, high efficiency means of milli-Kelvin cooling, requiring relatively little laboratory development.

Effects of Fab' fragments of specific egg yolk antibody (IgY-Fab') against Shewanella putrefaciens on the preservation of refrigerated turbot.

PubMed

Zhang, Qian; Lin, Hong; Sui, Jianxin; Wang, Jingxue; Cao, Limin

2015-01-01

In our previous studies the specific egg yolk antibody (IgY) against Shewanella putrefaciens (one of the specific spoilage organisms for marine products during aerobic chilling storage) demonstrated significant activity to prolong the shelf life of refrigerated fish. The exploitation of the antigen-binding fragment plus the hinge region (IgY-Fab') is now considered a promising method for improving the efficiency of such natural antimicrobial agents. The antimicrobial activity of IgY-Fab' against S. putrefaciens was investigated using refrigerated turbot as samples. By microbial, chemical and sensory tests, it was shown to be able to effectively inhibit bacterial growth and prolong the shelf life of samples, with an efficiency evaluated significantly higher than that of whole IgY with the same molarity. The interaction between IgY agents and S. putrefaciens cells was also investigated, and the IgY-Fab' showed a much greater ability to damage cell membranes than the whole IgY. Compared to whole IgY with the same molarity, IgY-Fab' demonstrated higher and more durable antimicrobial efficiency. Such a result was assumed to be closely related to its structural properties (such as the much lower molecular weight), which may enhance its ability to influence physiological activities of antigen bacteria, especially the property or/and structure of cell membranes. © 2014 Society of Chemical Industry.

Technology Application of Environmental Friendly Refrigeration (Green Refrigeration) on Cold Storage for Fishery Industry

NASA Astrophysics Data System (ADS)

Rasta, IM; Susila, IDM; Subagia, IWA

2018-01-01

The application of refrigeration technology to postharvest fishery products is an very important. Moreover, Indonesia is a tropical region with relatively high temperatures. Fish storage age can be prolonged with a decrease in temperature. Frozen fish can even be stored for several months. Fish freezing means preparing fish for storage in low-temperature cold storage. The working fluid used in cold storage to cool low-temperature chambers and throw heat into high-temperature environments is refrigerant. So far refrigerant used in cold storage is Hydrochloroflourocarbons (HCFC) that is R-22. Chlor is a gas that causes ODP (Ozone Depleting Potential), while Flour is a gas that causes GWP (Global Warming Potential). Government policy began in 2015 to implement Hydrochloroflourocarbons Phase-Out Management Plan. Hydrocarbon (HC) is an alternative substitute for R-22. HC-22 (propane ≥ 99.5%) has several advantages, among others: environmentally friendly, indicated by a zero ODP value, and GWP = 3 (negligible), thermophysical property and good heat transfer characteristics, vapor phase density Which is low, and good solubility with mineral lubricants. The use of HC-22 in cold storage is less than R-22. From the analysis results obtained, cold storage system using HC-22 has better performance and energy consumption is more efficient than the R-22.

Nitrogen expander cycles for large capacity liquefaction of natural gas

NASA Astrophysics Data System (ADS)

Chang, Ho-Myung; Park, Jae Hoon; Gwak, Kyung Hyun; Choe, Kun Hyung

2014-01-01

Thermodynamic study is performed on nitrogen expander cycles for large capacity liquefaction of natural gas. In order to substantially increase the capacity, a Brayton refrigeration cycle with nitrogen expander was recently added to the cold end of the reputable propane pre-cooled mixed-refrigerant (C3-MR) process. Similar modifications with a nitrogen expander cycle are extensively investigated on a variety of cycle configurations. The existing and modified cycles are simulated with commercial process software (Aspen HYSYS) based on selected specifications. The results are compared in terms of thermodynamic efficiency, liquefaction capacity, and estimated size of heat exchangers. The combination of C3-MR with partial regeneration and pre-cooling of nitrogen expander cycle is recommended to have a great potential for high efficiency and large capacity.

Process simulations for the LCLS-II cryogenic systems

NASA Astrophysics Data System (ADS)

Ravindranath, V.; Bai, H.; Heloin, V.; Fauve, E.; Pflueckhahn, D.; Peterson, T.; Arenius, D.; Bevins, M.; Scanlon, C.; Than, R.; Hays, G.; Ross, M.

2017-12-01

Linac Coherent Light Source II (LCLS-II), a 4 GeV continuous-wave (CW) superconducting electron linear accelerator, is to be constructed in the existing two mile Linac facility at the SLAC National Accelerator Laboratory. The first light from the new facility is scheduled to be in 2020. The LCLS-II Linac consists of thirty-five 1.3 GHz and two 3.9 GHz superconducting cryomodules. The Linac cryomodules require cryogenic cooling for the super-conducting niobium cavities at 2.0 K, low temperature thermal intercept at 5.5-7.5 K, and a thermal shield at 35-55 K. The equivalent 4.5 K refrigeration capacity needed for the Linac operations range from a minimum of 11 kW to a maximum of 24 kW. Two cryogenic plants with 18 kW of equivalent 4.5 K refrigeration capacity will be used for supporting the Linac cryogenic cooling requirements. The cryogenic plants are based on the Jefferson Lab’s CHL-II cryogenic plant design which uses the “Floating Pressure” design to support a wide variation in the cooling load. In this paper, the cryogenic process for the integrated LCLS-II cryogenic system and the process simulation for a 4.5 K cryoplant in combination with a 2 K cold compressor box, and the Linac cryomodules are described.

Progress on Fuel Efficiency and Market Adoption - SuperTruck Factsheet

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2016-06-30

The Department of Energy (DOE) launched the SuperTruck initiative in 2009 with the goal of developing and demonstrating a 50 percent improvement in overall freight efficiency (expressed in a ton-mile per gallon metric) for a heavy-duty Class 8 tractor-trailer. To date, the industry teams participating in the initiative have successfully met or are on track to exceed this goal, leveraging suites of technologies that hold significant potential for market success.

Computational tool for simulation of power and refrigeration cycles

NASA Astrophysics Data System (ADS)

Córdoba Tuta, E.; Reyes Orozco, M.

2016-07-01

Small improvement in thermal efficiency of power cycles brings huge cost savings in the production of electricity, for that reason have a tool for simulation of power cycles allows modeling the optimal changes for a best performance. There is also a big boom in research Organic Rankine Cycle (ORC), which aims to get electricity at low power through cogeneration, in which the working fluid is usually a refrigerant. A tool to design the elements of an ORC cycle and the selection of the working fluid would be helpful, because sources of heat from cogeneration are very different and in each case would be a custom design. In this work the development of a multiplatform software for the simulation of power cycles and refrigeration, which was implemented in the C ++ language and includes a graphical interface which was developed using multiplatform environment Qt and runs on operating systems Windows and Linux. The tool allows the design of custom power cycles, selection the type of fluid (thermodynamic properties are calculated through CoolProp library), calculate the plant efficiency, identify the fractions of flow in each branch and finally generates a report very educational in pdf format via the LaTeX tool.

Near-field refrigeration and tunable heat exchange through four-wave mixing

NASA Astrophysics Data System (ADS)

Khandekar, Chinmay; Messina, Riccardo; Rodriguez, Alejandro W.

2018-05-01

We modify and extend a recently proposed four-wave mixing scheme [C. Khandekar and A. Rodriguez, Opt. Express 25(19), 23164 (2017)] for achieving near-field thermal upconversion and energy transfer, to demonstrate efficient thermal refrigeration at low intensities ˜ 109W/m2 over a wide range of gap sizes (from tens to hundreds of nanometers) and operational temperatures (from tens to hundreds of Kelvins). We further exploit the scheme to achieve magnitude and directional tunability of near-field heat exchange between bodies held at different temperatures.

Feasibility analysis of a Commercial HPWH with CO 2 Refrigerant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nawaz, Kashif; Shen, Bo; Elatar, Ahmed F.

2017-02-12

A scoping-level analysis has conducted to establish the feasibility of using CO 2 as refrigerant for a commercial heat pump water heater (HPWH) for U.S. applications. The DOE/ORNL Heat Pump Design Model (HPDM) modeling tool was used for the assessment with data from a Japanese heat pump water heater (Sanden) using CO 2 as refrigerant for calibration. A CFD modeling tool was used to further refine the HPDM tank model. After calibration, the model was used to simulate the performance of commercial HPWHs using CO 2 and R-134a (baseline). The parametric analysis concluded that compressor discharge pressure and water temperaturemore » stratification are critical parameters for the system. For comparable performance the compressor size and water-heater size can be significantly different for R-134 and CO 2 HPWHs. The proposed design deploying a gas-cooler configuration not only exceeds the Energy Star Energy Factor criteria i.e. 2.20, but is also comparable to some of the most efficient products in the market using conventional refrigerants.« less

Advanced Refrigerant-Based Cooling Technologies for Information and Communication Infrastructure (ARCTIC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salamon, Todd

2012-12-13

Faster, more powerful and dense computing hardware generates significant heat and imposes considerable data center cooling requirements. Traditional computer room air conditioning (CRAC) cooling methods are proving increasingly cost-ineffective and inefficient. Studies show that using the volume of room air as a heat exchange medium is wasteful and allows for substantial mixing of hot and cold air. Further, it limits cabinet/frame/rack density because it cannot effectively cool high heat density equipment that is spaced closely together. A more cost-effective, efficient solution for maximizing heat transfer and enabling higher heat density equipment frames can be accomplished by utilizing properly positioned phasemore » change or two-phase pumped refrigerant cooling methods. Pumping low pressure, oil-free phase changing refrigerant through microchannel heat exchangers can provide up to 90% less energy consumption for the primary cooling loop within the room. The primary benefits of such a solution include reduced energy requirements, optimized utilization of data center space, and lower OPEX and CAPEX. Alcatel-Lucent recently developed a modular cooling technology based on a pumped two-phase refrigerant that removes heat directly at the shelf level of equipment racks. The key elements that comprise the modular cooling technology consist of the following. A pump delivers liquid refrigerant to finned microchannel heat exchangers mounted on the back of equipment racks. Fans drive air through the equipment shelf, where the air gains heat dissipated by the electronic components therein. Prior to exiting the rack, the heated air passes through the heat exchangers, where it is cooled back down to the temperature level of the air entering the frame by vaporization of the refrigerant, which is subsequently returned to a condenser where it is liquefied and recirculated by the pump. All the cooling air enters and leaves the shelves/racks at nominally the same temperature. Results of a 100 kW prototype data center installation of the refrigerant-based modular cooling technology were dramatic in terms of energy efficiency and the ability to cool high-heat-density equipment. The prototype data center installation consisted of 10 racks each loaded with 10 kW of high-heat-density IT equipment with the racks arranged in a standard hot-aisle/cold-aisle configuration with standard cabinet spacing. A typical chilled-water CRAC unit would require approximately 16 kW to cool such a heat load. In contrast, the refrigerant-based modular cooling technology required only 2.3 kW of power for the refrigerant pump and shelf-level fans, a reduction of 85 percent. Differences in hot-aisle and cold-aisle temperature were also substantially reduced, mitigating many issues that arise in purely air-based cooling systems, such as mixing of hot and cold air streams, or from placing high-heat-density equipment in close proximity. The technology is also such that it is able to retro-fit live equipment without service interruption, which is particularly important to the large installed ICT customer base, thereby providing a means of mitigating reliability and performance concerns during the installation, training and validation phases of product integration. Moreover, the refrigerant used in our approach, R134a, is a widely-used, non-toxic dielectric liquid which, unlike water, is non-conducting and non-corrosive and will not damage electronics in the case of a leak a triple-play win over alternative water-based liquid coolant technologies. Finally, through use of a pumped refrigerant, pressures are modest (~60 psi), and toxic lubricants and oils are not required, in contrast to compressorized refrigerant systems another environmental win. Project Activities - The ARCTIC project goal was to further develop and dramatically accelerate the commercialization of this game-changing, refrigerant-based, liquid-cooling technology and achieve a revolutionary increase in energy efficiency and carbon footprint reduction for our nation's Information and Communications Technology (ICT) infrastructure. The specific objectives of the ARCTIC project focused in the following three areas: i) advanced research innovations that dramatically enhance the ability to deal with ever-increasing device heat densities and footprint reduction by bringing the liquid cooling much closer to the actual heat sources; ii) manufacturing optimization of key components; and iii) ensuring rapid market acceptance by reducing cost, thoroughly understanding system-level performance, and developing viable commercialization strategies. The project involved participants with expertise in all aspects of commercialization, including research & development, manufacturing, sales & marketing and end users. The team was lead by Alcatel-Lucent, and included subcontractors Modine and USHose.« less

An Invitation to Imitation

DTIC Science & Technology

2015-03-15

Super Mario Bros, 2010b. URL http://www.youtube.com/watch?v=anOI0xZ3kGM. S. Ross and J. A. Bagnell. Efficient reductions for imitation learning. In...learning to drive a car in a video game by performing a direct mapping from screen shots to steering angles. Figure 4 illustrates the classic super - an...same distribution and thus the super - vised learning assumption of independent and identically distributed (i.i.d.) data is badly violated. A natural

Development and Applications of a Modular Parallel Process for Large Scale Fluid/Structures Problems

NASA Technical Reports Server (NTRS)

Guruswamy, Guru P.; Byun, Chansup; Kwak, Dochan (Technical Monitor)

2001-01-01

A modular process that can efficiently solve large scale multidisciplinary problems using massively parallel super computers is presented. The process integrates disciplines with diverse physical characteristics by retaining the efficiency of individual disciplines. Computational domain independence of individual disciplines is maintained using a meta programming approach. The process integrates disciplines without affecting the combined performance. Results are demonstrated for large scale aerospace problems on several supercomputers. The super scalability and portability of the approach is demonstrated on several parallel computers.

A regenerative elastocaloric heat pump

NASA Astrophysics Data System (ADS)

Tušek, Jaka; Engelbrecht, Kurt; Eriksen, Dan; Dall'Olio, Stefano; Tušek, Janez; Pryds, Nini

2016-10-01

A large fraction of global energy use is for refrigeration and air-conditioning, which could be decarbonized if efficient renewable energy technologies could be found. Vapour-compression technology remains the most widely used system to move heat up the temperature scale after more than 100 years; however, caloric-based technologies (those using the magnetocaloric, electrocaloric, barocaloric or elastocaloric effect) have recently shown a significant potential as alternatives to replace this technology due to high efficiency and the use of green solid-state refrigerants. Here, we report a regenerative elastocaloric heat pump that exhibits a temperature span of 15.3 K on the water side with a corresponding specific heating power up to 800 W kg-1 and maximum COP (coefficient-of-performance) values of up to 7. The efficiency and specific heating power of this device exceeds those of other devices based on caloric effects. These results open up the possibility of using the elastocaloric effect in various cooling and heat-pumping applications.

On the Use of Thermoelectric (TE) Applications Based on Commercial Modules: The Case of TE Generator and TE Cooler

NASA Astrophysics Data System (ADS)

Zorbas, K.; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Kyratsi, Th.

2010-01-01

In recent years, thermoelectricity sees rapidly increasing usages in applications like portable refrigerators, beverage coolers, electronic component coolers etc. when used as Thermoelectric Cooler (TEC), and Thermoelectric Generators (TEG) which make use of the Seebeck effect in semiconductors for the direct conversion of heat into electrical energy and is of particular interest for systems of highest reliability or for waste heat recovery. In this work, we examine the performance of commercially available TEC and TEG. A prototype TEC-refrigerator has been designed, modeled and constructed for in-car applications. Additionally, a TEG was made, in order to measure the gained power and efficiency. Furthermore, a TEG module was tested on a small size car (Toyota Starlet, 1300 cc), in order to measure the gained power and efficiency for various engine loads. With the use of a modeling approach, we evaluated the thermal contact resistances and their influence on the final device efficiency.

Analytical method validation for the determination of 2,3,3,3-tetrafluoropropene in air samples using gas chromatography with flame ionization detection.

PubMed

Mawn, Michael P; Kurtz, Kristine; Stahl, Deborah; Chalfant, Richard L; Koban, Mary E; Dawson, Barbara J

2013-01-01

A new low global warming refrigerant, 2,3,3,3-tetrafluoro propene, or HFO-1234yf, has been successfully evaluated for automotive air conditioning, and is also being evaluated for stationary refrigeration and air conditioning systems. Due to the advantageous environmental properties of HFO-1234yf versus HFC-134a, coupled with its similar physical properties and system performance, HFO-1234yf is also being evaluated to replace HFC-134a in refrigeration applications where neat HFC-134a is currently used. This study reports on the development and validation of a sampling and analytical method for the determination of HFO-1234yf in air. Different collection media were screened for desorption and simulated sampling efficiency with three-section (350/350/350 mg) Anasorb CSC showing the best results. Therefore, air samples were collected using two 3-section Anasorb CSC sorbent tubes in series at 0.02 L/min for up to 8 hr for sample volumes of up to 9.6 L. The sorbent tubes were extracted in methylene chloride, and analyzed by gas chromatography with flame ionization detection. The method was validated from 0.1× to 20× the target level of 0.5 ppm (2.3 mg/m(3)) for a 9.6 L air volume. Desorption efficiencies for HFO-1234yf were 88 to 109% for all replicates over the validation range with a mean overall recovery of 93%. Simulated sampling efficiencies ranged from 87 to 104% with a mean of 94%. No migration or breakthrough to the back tube was observed under the sampling conditions evaluated. HFO-1234yf samples showed acceptable storage stability on Anasorb CSC sorbent up to a period of 30 days when stored under ambient, refrigerated, or frozen temperature conditions.

Design of China Leading Energy Efficiency Program (LEP) for equipment and appliances and comparative study of international experience on super-efficient products

NASA Astrophysics Data System (ADS)

Liang, Xiuying; Zhu, Chunyan

2017-11-01

With rising global emphasizes on climate change and sustainable development, how to accelerate the transformation of energy efficiency has become an important question. Designing and implementing energy-efficiency policies for super-efficient products represents an important direction to achieve breakthroughs in the field of energy conservation. On December 31, 2014, China’s National Development and Reform Commission (NDRC) jointly six other ministerial agencies launched China Leading Energy Efficiency Program (LEP), which identifies top efficiency models for selected product categories. LEP sets the highest energy efficiency benchmark. Design of LEP took into consideration of how to best motivate manufacturers to accelerate technical innovation, promote high efficiency products. This paper explains core elements of LEP, such as objectives, selection criteria, implementation method and supportive policies. It also proposes recommendations to further improve LEP through international policy comparison with Japan’s Top Runner Program, U.S. Energy Star Most Efficient, and SEAD Global Efficiency Medal.

Heat-machine control by quantum-state preparation: from quantum engines to refrigerators.

PubMed

Gelbwaser-Klimovsky, D; Kurizki, G

2014-08-01

We explore the dependence of the performance bounds of heat engines and refrigerators on the initial quantum state and the subsequent evolution of their piston, modeled by a quantized harmonic oscillator. Our goal is to provide a fully quantized treatment of self-contained (autonomous) heat machines, as opposed to their prevailing semiclassical description that consists of a quantum system alternately coupled to a hot or a cold heat bath and parametrically driven by a classical time-dependent piston or field. Here, by contrast, there is no external time-dependent driving. Instead, the evolution is caused by the stationary simultaneous interaction of two heat baths (having distinct spectra and temperatures) with a single two-level system that is in turn coupled to the quantum piston. The fully quantized treatment we put forward allows us to investigate work extraction and refrigeration by the tools of quantum-optical amplifier and dissipation theory, particularly, by the analysis of amplified or dissipated phase-plane quasiprobability distributions. Our main insight is that quantum states may be thermodynamic resources and can provide a powerful handle, or control, on the efficiency of the heat machine. In particular, a piston initialized in a coherent state can cause the engine to produce work at an efficiency above the Carnot bound in the linear amplification regime. In the refrigeration regime, the coefficient of performance can transgress the Carnot bound if the piston is initialized in a Fock state. The piston may be realized by a vibrational mode, as in nanomechanical setups, or an electromagnetic field mode, as in cavity-based scenarios.

Heat-machine control by quantum-state preparation: From quantum engines to refrigerators

NASA Astrophysics Data System (ADS)

Gelbwaser-Klimovsky, D.; Kurizki, G.

2014-08-01

We explore the dependence of the performance bounds of heat engines and refrigerators on the initial quantum state and the subsequent evolution of their piston, modeled by a quantized harmonic oscillator. Our goal is to provide a fully quantized treatment of self-contained (autonomous) heat machines, as opposed to their prevailing semiclassical description that consists of a quantum system alternately coupled to a hot or a cold heat bath and parametrically driven by a classical time-dependent piston or field. Here, by contrast, there is no external time-dependent driving. Instead, the evolution is caused by the stationary simultaneous interaction of two heat baths (having distinct spectra and temperatures) with a single two-level system that is in turn coupled to the quantum piston. The fully quantized treatment we put forward allows us to investigate work extraction and refrigeration by the tools of quantum-optical amplifier and dissipation theory, particularly, by the analysis of amplified or dissipated phase-plane quasiprobability distributions. Our main insight is that quantum states may be thermodynamic resources and can provide a powerful handle, or control, on the efficiency of the heat machine. In particular, a piston initialized in a coherent state can cause the engine to produce work at an efficiency above the Carnot bound in the linear amplification regime. In the refrigeration regime, the coefficient of performance can transgress the Carnot bound if the piston is initialized in a Fock state. The piston may be realized by a vibrational mode, as in nanomechanical setups, or an electromagnetic field mode, as in cavity-based scenarios.

Evidence of progress. Measurement of impacts of Australia's S and L program from 1990-2010

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowenthal-Savy; McNeil, Michael; Harrington, Lloyd

2013-10-15

Australia first put categorical energy efficiency labels on residential appliances in the mid-1980s, and the first Minimum Energy Performance Standards (MEPS) for refrigerators was implemented in 1999. Updated in 2005, these MEPS were aligned with US 2001 levels. Considered together, these actions set Australia apart as having one of the most aggressive appliance efficiency programs in the world. For these reasons, together with good data on product sales over time, Australia represents a potentially fruitful case study for understanding the dynamics energy efficiency standards and labeling (EES and L) programs impacts on appliance markets. This analysis attempts to distinguish betweenmore » the impacts of labeling alone as opposed to MEPS, and to probe the time-dependency of such impacts. Fortunately, in the Australian case, detailed market sales data and a comprehensive registration system provides a solid basis for the empirical evaluation of these questions. This paper analyzes Australian refrigerator efficiency data covering the years 1993-2009. Sales data was purchased from a commercial market research organization (in this case, the GfK Group) and includes sales and average price in each year for each appliance model – this can be used to understand broader trends by product class and star rating category, even where data is aggregated. Statistical regression analysis is used to model market introduction and adoption of high efficiency refrigerators according to logistic adoption model formalism, and parameterizes the way in which the Australian programs accelerated adoption of high-efficiency products and phased out others. Through this analysis, the paper presents a detailed, robust and quantitative picture of the impacts of EES and L in the Australian case, but also demonstrates a methodology of the evaluation of program impacts that could form the basis of an international evaluation framework for similar programs in other countries.« less

Evidence of Progress - Measurement of Impacts of Australia's S&L Program from 1990-2010

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowenthal-Savy, Danielle; McNeil, Michael; Harrington, Lloyd

2013-09-11

Australia first put categorical energy efficiency labels on residential appliances in the mid-1980s, and the first Minimum Energy Performance Standards (MEPS) for refrigerators was implemented in 1999. Updated in 2005, these MEPS were aligned with US 2001 levels. Considered together, these actions set Australia apart as having one of the most aggressive appliance efficiency programs in the world. For these reasons, together with good data on product sales over time, Australia represents a potentially fruitful case study for understanding the dynamics energy efficiency standards and labeling (EES&L) programs impacts on appliance markets. This analysis attempts to distinguish between the impactsmore » of labeling alone as opposed to MEPS, and to probe the time-dependency of such impacts. Fortunately, in the Australian case, detailed market sales data and a comprehensive registration system provides a solid basis for the empirical evaluation of these questions. This paper analyzes Australian refrigerator efficiency data covering the years 1993-2009. Sales data was purchased from a commercial market research organization (in this case, the GfK Group) and includes sales and average price in each year for each appliance model; this can be used to understand broader trends by product class and star rating category, even where data is aggregated. Statistical regression analysis is used to model market introduction and adoption of high efficiency refrigerators according to logistic adoption model formalism, and parameterizes the way in which the Australian programs accelerated adoption of high-efficiency products and phased out others. Through this analysis, the paper presents a detailed, robust and quantitative picture of the impacts of EES&L in the Australian case, but also demonstrates a methodology of the evaluation of program impacts that could form the basis of an international evaluation framework for similar programs in other countries.« less

Super: a web server to rapidly screen superposable oligopeptide fragments from the protein data bank.

PubMed

Collier, James H; Lesk, Arthur M; Garcia de la Banda, Maria; Konagurthu, Arun S

2012-07-01

Searching for well-fitting 3D oligopeptide fragments within a large collection of protein structures is an important task central to many analyses involving protein structures. This article reports a new web server, Super, dedicated to the task of rapidly screening the protein data bank (PDB) to identify all fragments that superpose with a query under a prespecified threshold of root-mean-square deviation (RMSD). Super relies on efficiently computing a mathematical bound on the commonly used structural similarity measure, RMSD of superposition. This allows the server to filter out a large proportion of fragments that are unrelated to the query; >99% of the total number of fragments in some cases. For a typical query, Super scans the current PDB containing over 80,500 structures (with ∼40 million potential oligopeptide fragments to match) in under a minute. Super web server is freely accessible from: http://lcb.infotech.monash.edu.au/super.

Active magnetic regenerator

DOEpatents

Barclay, John A.; Steyert, William A.

1982-01-01

The disclosure is directed to an active magnetic regenerator apparatus and method. Brayton, Stirling, Ericsson, and Carnot cycles and the like may be utilized in an active magnetic regenerator to provide efficient refrigeration over relatively large temperature ranges.

Thermodynamic design of natural gas liquefaction cycles for offshore application

NASA Astrophysics Data System (ADS)

Chang, Ho-Myung; Lim, Hye Su; Choe, Kun Hyung

2014-09-01

A thermodynamic study is carried out for natural gas liquefaction cycles applicable to offshore floating plants, as partial efforts of an ongoing governmental project in Korea. For offshore liquefaction, the most suitable cycle may be different from the on-land LNG processes under operation, because compactness and simple operation are important as well as thermodynamic efficiency. As a turbine-based cycle, closed Claude cycle is proposed to use NG (natural gas) itself as refrigerant. The optimal condition for NG Claude cycle is determined with a process simulator (Aspen HYSYS), and the results are compared with fully-developed C3-MR (propane pre-cooled mixed refrigerant) JT cycles and various N2 (nitrogen) Brayton cycles in terms of efficiency and compactness. The newly proposed NG Claude cycle could be a good candidate for offshore LNG processes.

Magnetorheological elastic super-smooth finishing for high-efficiency manufacturing of ultraviolet laser resistant optics

NASA Astrophysics Data System (ADS)

Shi, Feng; Shu, Yong; Dai, Yifan; Peng, Xiaoqiang; Li, Shengyi

2013-07-01

Based on the elastic-plastic deformation theory, status between abrasives and workpiece in magnetorheological finishing (MRF) process and the feasibility of elastic polishing are analyzed. The relationship among material removal mechanism and particle force, removal efficiency, and surface topography are revealed through a set of experiments. The chemical dominant elastic super-smooth polishing can be fulfilled by changing the components of magnetorheological (MR) fluid and optimizing polishing parameters. The MR elastic super-smooth finishing technology can be applied in polishing high-power laser-irradiated components with high efficiency, high accuracy, low damage, and high laser-induced damage threshold (LIDT). A 430×430×10 mm fused silica (FS) optic window is polished and surface error is improved from 538.241 nm [peak to valley (PV)], 96.376 nm (rms) to 76.372 nm (PV), 8.295 nm (rms) after 51.6 h rough polishing, 42.6 h fine polishing, and 54.6 h super-smooth polishing. A 50×50×10 mm sample is polished with exactly the same parameters. The roughness is improved from 1.793 nm [roughness average (Ra)] to 0.167 nm (Ra) and LIDT is improved from 9.77 to 19.2 J/cm2 after MRF elastic polishing.

dbSUPER: a database of super-enhancers in mouse and human genome

PubMed Central

Khan, Aziz; Zhang, Xuegong

2016-01-01

Super-enhancers are clusters of transcriptional enhancers that drive cell-type-specific gene expression and are crucial to cell identity. Many disease-associated sequence variations are enriched in super-enhancer regions of disease-relevant cell types. Thus, super-enhancers can be used as potential biomarkers for disease diagnosis and therapeutics. Current studies have identified super-enhancers in more than 100 cell types and demonstrated their functional importance. However, a centralized resource to integrate all these findings is not currently available. We developed dbSUPER (http://bioinfo.au.tsinghua.edu.cn/dbsuper/), the first integrated and interactive database of super-enhancers, with the primary goal of providing a resource for assistance in further studies related to transcriptional control of cell identity and disease. dbSUPER provides a responsive and user-friendly web interface to facilitate efficient and comprehensive search and browsing. The data can be easily sent to Galaxy instances, GREAT and Cistrome web-servers for downstream analysis, and can also be visualized in the UCSC genome browser where custom tracks can be added automatically. The data can be downloaded and exported in variety of formats. Furthermore, dbSUPER lists genes associated with super-enhancers and also links to external databases such as GeneCards, UniProt and Entrez. dbSUPER also provides an overlap analysis tool to annotate user-defined regions. We believe dbSUPER is a valuable resource for the biology and genetic research communities. PMID:26438538

Fabrication of TiO2/EP super-hydrophobic thin film on filter paper surface.

PubMed

Gao, Zhengxin; Zhai, Xianglin; Liu, Feng; Zhang, Ming; Zang, Deli; Wang, Chengyu

2015-09-05

A composite filter paper with super-hydrophobicity was obtained by adhering micro/nano structure of amorphous titanium dioxide on the filter paper surface with modifying low surface energy material. By virtue of the coupling agent, which plays an important part in bonding amorphous titanium dioxide and epoxy resin, the structure of super-hydrophobic thin film on the filter paper surface is extremely stable. The microstructure of super-hydrophobic filter paper was characterized by scanning electron microscopy (SEM), the images showed that the as-prepared filter paper was covered with uniform amorphous titanium dioxide particles, generating a roughness structure on the filter paper surface. The super-hydrophobic performance of the filter paper was characterized by water contact angle measurements. The observations showed that the wettability of filter paper samples transformed from super-hydrophilicity to super-hydrophobicity with the water contact angle of 153 ± 1°. Some experiments were also designed to test the effect of water-oil separation and UV-resistant by the super-hydrophobic filter paper. The prepared super-hydrophobic filter paper worked efficiently and simply in water-oil separation as well as enduringly in anti-UV property after the experiments. This method offers an opportunity to the practical applications of the super-hydrophobic filter paper. Copyright © 2015 Elsevier Ltd. All rights reserved.

Applications of the Magnetocaloric Effect in Single-Stage, Multi-Stage and Continuous Adiabatic Demagnetization Refrigerators

NASA Technical Reports Server (NTRS)

Shirron, Peter J.

2014-01-01

Adiabatic demagnetization refrigerators (ADR), based on the magnetocaloric effect, are solid-state coolers that were the first to achieve cooling well into the sub-kelvin regime. Although supplanted by more powerful dilution refrigerators in the 1960s, ADRs have experienced a revival due to the needs of the space community for cooling astronomical instruments and detectors to temperatures below 100 mK. The earliest of these were single-stage refrigerators using superfluid helium as a heat sink. Their modest cooling power (<1 µW at 60 mK[1]) was sufficient for the small (6x6) detector arrays[2], but recent advances in arraying and multiplexing technologies[3] are generating a need for higher cooling power (5-10 µW), and lower temperature (<30 mK). Single-stage ADRs have both practical and fundamental limits to their operating range, as mass grows very rapidly as the operating range is expanded. This has led to the development of new architectures that introduce multi-staging as a way to improve operating range, efficiency and cooling power. Multi-staging also enables ADRs to be configured for continuous operation, which greatly improves cooling power per unit mass. This paper reviews the current field of adiabatic demagnetization refrigeration, beginning with a description of the magnetocaloric effect and its application in single-stage systems, and then describing the challenges and capabilities of multi-stage and continuous ADRs.

An application of gap regenerator/expander precooled by two stage G-M refrigerator

NASA Technical Reports Server (NTRS)

Matsubara, Y.; Yasukochi, K.

1983-01-01

The degradation of regenerator effectiveness below 10K is due to the imbalance of the heat capacity of the regenerator material and helium gas as a working fluid. One of the attractive methods to increase this efficiency could be realized by a gap regenerator system regarding helium gas property. This paper describes an experiment using pressurized helium gas as a regenerator material. A two stage G-M cycle refrigerator has been used for precooling the gap regenerator system. With this method, minimum temperature below 5K has been obtained when the precooling temperature maintained at 10K.

Absorption generator for solar-powered air-conditioner

NASA Technical Reports Server (NTRS)

Lowen, D. J.; Murray, J. G.

1977-01-01

Device passes solar-heated water through coils. Hot lithium Bromide/Water solution leaves through central stand-pipe, and water vapor leaves through refrigerant outlet at top. Matching generation temperature to collector efficiency helps cut costs.

Niobium Solar Mobile Project — High Strength Niobium Microalloyed Steel as a Solution to Improve Electric Super Scooter and Motorcycle Performance

NASA Astrophysics Data System (ADS)

Richards, Terry; Kauppi, Erik; Flanagan, Lauren; Ribeio, Eduardo A. A. G.; Nogueira, Marcos A. Stuart; McCourtney, Ian

This paper presents the advantages of replacing mild steel with high strength niobium microalloyed steel in the structure of Electric Super Scooters, Electric Cargo Motorcycles and Solar Charging Stations. The Mini-Fleet-in-a-Box concept was developed by Current Motor to guarantee mobility, efficiency and solar generated electricity. With the adoption of niobium microalloyed high strength steel for more than 90% of the Super Scooter and Motorcycle structures, it was possible to redesign the frame, resulting in a 31% weight reduction and a very modern and functional body. Together with a new powertrain, these changes were responsible for increasing Motorcycle autonomy by more than 15%, depending on average speed. The new frame design reduced the number of high strain points in the frame, increasing the safety of the project. The Solar Charging Station was built using the container concept and designed with high strength niobium microalloyed steel, which resulted in a weight reduction of 25%. CBMM's facility in Araxá, Brazil was selected in the second half of 2013 as the demonstration site to test the efficiency of the Super Scooter and Solar Charging Station. Each Super Scooter has run more than 2,000 km maintenance-free with an autonomy of more than 100 km per charge.

Effect of trailing edge thickness on the performance of a helium turboexpander used in cryogenic refrigeration and liquefaction cycles

NASA Astrophysics Data System (ADS)

Sam, Ashish Alex; Ghosh, Parthasarathi

2017-02-01

Turboexpanders in cryogenic refrigeration and liquefaction cycles, which is of radial inflow configuration, constitute stationary and rotating components like nozzle, a rotating wheel and a diffuser. The relative motion between the stationary and rotating components and the interactions of secondary flows and vortices at different stages make the turboexpander flow unsteady. Computational Fluid Dynamics (CFD) analysis of this flow is essential to identify the scope for improvement in efficiency. The trailing edge vortex formed due to the mixing of the pressure and suction side streams is an important phenomenon to analyse, as this leads to efficiency degradation of the machine. Additionally, there are mechanical vibrations and dynamic loading associated with. This flow non-uniformity at the exit should be suppressed as this may affect the pressure recovery process in the diffuser and thereby the turboexpander’s performance. The strength of this vortex depends upon the geometrical parameters like trailing edge shape, thickness etc. In this paper, transient CFD analyses of a cryogenic turboexpander designed for helium refrigeration and liquefaction cycles using Ansys CFX® were performed to investigate the effect of trailing edge thickness on the turboexpander performance and the performance characteristics and the flow patterns were compared to understand the flow characteristics in each case.

SuperSpec, The On-Chip Spectrometer: Improved NEP and Antenna Performance

NASA Astrophysics Data System (ADS)

Wheeler, Jordan; Hailey-Dunsheath, S.; Shirokoff, E.; Barry, P. S.; Bradford, C. M.; Chapman, S.; Che, G.; Doyle, S.; Glenn, J.; Gordon, S.; Hollister, M.; Kovács, A.; LeDuc, H. G.; Mauskopf, P.; McGeehan, R.; McKenney, C.; Reck, T.; Redford, J.; Ross, C.; Shiu, C.; Tucker, C.; Turner, J.; Walker, S.; Zmuidzinas, J.

2018-05-01

SuperSpec is a new technology for mm and sub-mm spectroscopy. It is an on-chip spectrometer being developed for multi-object, moderate-resolution (R˜ 300 ), large bandwidth survey spectroscopy of high-redshift galaxies for the 1 mm atmospheric window. This band accesses the CO ladder in the redshift range of z = 0-4 and the [CII] 158 μm line from redshift z = 5-9. SuperSpec employs a novel architecture in which detectors are coupled to a series of resonant filters along a single microwave feedline instead of using dispersive optics. This construction allows for the creation of a full spectrometer occupying only ˜ 10 cm^2 of silicon, a reduction in size of several orders of magnitude when compared to standard grating spectrometers. This small profile enables the production of future multi-beam spectroscopic instruments envisioned for the millimeter band to measure the redshifts of dusty galaxies efficiently. The SuperSpec collaboration is currently pushing toward the deployment of a SuperSpec demonstration instrument in fall of 2018. The progress with the latest SuperSpec prototype devices is presented; reporting increased responsivity via a reduced inductor volume (2.6 μm^3 ) and the incorporation of a new broadband antenna. A detector NEP of 3-4 × 10^{-18} W/Hz^{0.5} is obtained, sufficient for background-limited observation on mountaintop sites. In addition, beam maps and efficiency measurements of a new wide-band dual bow-tie slot antenna are shown.

"Supertrap" at Work: Extremely Efficient Nonradiative Recombination Channels in MAPbI3 Perovskites Revealed by Luminescence Super-Resolution Imaging and Spectroscopy.

PubMed

Merdasa, Aboma; Tian, Yuxi; Camacho, Rafael; Dobrovolsky, Alexander; Debroye, Elke; Unger, Eva L; Hofkens, Johan; Sundström, Villy; Scheblykin, Ivan G

2017-06-27

Organo-metal halide perovskites are some of the most promising materials for the new generation of low-cost photovoltaic and light-emitting devices. Their solution processability is a beneficial trait, although it leads to a spatial inhomogeneity of perovskite films with a variation of the trap state density at the nanoscale. Comprehending their properties using traditional spectroscopy therefore becomes difficult, calling for a combination with microscopy in order to see beyond the ensemble-averaged response. We studied photoluminescence (PL) blinking of micrometer-sized individual methylammonium lead iodide (MAPbI 3 ) perovskite polycrystals, as well as monocrystalline microrods up to 10 μm long. We correlated their PL dynamics with structure employing scanning electron and optical super-resolution microscopy. Combining super-resolution localization imaging and super-resolution optical fluctuation imaging (SOFI), we could detect and quantify preferential emitting regions in polycrystals exhibiting different types of blinking. We propose that blinking in MAPbI 3 occurs by the activation/passivation of a "supertrap" which presumably is a donor-acceptor pair able to trap both electrons and holes. As such, nonradiative recombination via supertraps, in spite being present at a rather low concentrations (10 12 -10 15 cm -3 ), is much more efficient than via all other defect states present in the material at higher concentrations (10 16 -10 18 cm -3 ). We speculate that activation/deactivation of a supertrap occurs by its temporary dissociation into free donor and acceptor impurities. We found that supertraps are most efficient in structurally homogeneous and large MAPbI 3 crystals where carrier diffusion is efficient, which may therefore pose limitations on the efficiency of perovskite-based devices.

Design study of an YBCO-coated beam screen for the super proton-proton collider bending magnets

NASA Astrophysics Data System (ADS)

Gan, Pingping; Zhu, Kun; Fu, Qi; Li, Haipeng; Lu, Yuanrong; Easton, Matt; Liu, Yudong; Tang, Jingyu; Xu, Qingjin

2018-04-01

In order to reduce the beam impedance and refrigeration power dramatically, we have designed a high temperature superconductor (HTS) coated beam screen to screen the cold chamber walls of the super proton-proton collider bending magnets from beam-induced heat loads. It employs an absorber, inspired by the future circular collider studies, to absorb the immense synchrotron radiation power of 12.8 W/m emitted from the 37.5 TeV proton beams. Such a structure has the advantage of decreasing the electron cloud effect and improving the beam vacuum. We have compared the critical magnetic field and current density and accessibility of two potential HTS materials for the beam screen, TlBa2Ca2Cu3O9-δ (Tl-1223) and Yttrium Barium Copper Oxide (YBCO) and finally chose YBCO for coating. The beam screen is tentatively designed to work at 55-70 K because of the limited development of the YBCO material. The thermal analysis with oxygen cooling fluid indicates that the YBCO conductor can maintain its superconductivity even if the synchrotron radiation hits the YBCO-coated surface and the mechanical analysis shows that the structure has the ability to resist the Lorenz force during magnet quenches.

Cu mesh's super-hydrophobic and oleophobic properties with variations in gravitational pressure and surface components for oil/water separation applications

NASA Astrophysics Data System (ADS)

Guo, Wei; Zhang, Qin; Xiao, Haibo; Xu, Jie; Li, Qintao; Pan, Xiaohui; Huang, Zhiyong

2014-09-01

The super-hydrophobic and super-oleophilic properties of various materials have been utilized to separate oil from water. These properties induce both oil penetration and water slide off. This research demonstrates that the mesh with both super-hydrophobic and oleophobic properties, with a water contact angle (WCA) higher than 150° and oil contact angle (OCA) near 140°, can also be used to separate oil from. Oil has a higher probability than water of entering into the interstice of the Cu mesh surface and passing through it due to the capillarity effect, van der Waals attractions and the effects of gravitational pressure. The modified mesh surface can easily adsorb the oil, which then forms a film, due to the very strong adhesion properties of the oil molecules. The oil film then contributes to the water sliding off. These properties can be used to separate oil from water with separation efficiencies reaching 99.3%. Additionally, the separation of an oil/water mixture using sand permeated with oil yielded separation efficiencies exceeding 90%.

Powering a Home with Just 25 Watts of Solar PV. Super-Efficient Appliances Can Enable Expanded Off-Grid Energy Service Using Small Solar Power Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phadke, Amol A.; Jacobson, Arne; Park, Won Young

Highly efficient direct current (DC) appliances have the potential to dramatically increase the affordability of off-grid solar power systems used for rural electrification in developing countries by reducing the size of the systems required. For example, the combined power requirement of a highly efficient color TV, four DC light emitting diode (LED) lamps, a mobile phone charger, and a radio is approximately 18 watts and can be supported by a small solar power system (at 27 watts peak, Wp). Price declines and efficiency advances in LED technology are already enabling rapidly increased use of small off-grid lighting systems in Africamore » and Asia. Similar progress is also possible for larger household-scale solar home systems that power appliances such as lights, TVs, fans, radios, and mobile phones. When super-efficient appliances are used, the total cost of solar home systems and their associated appliances can be reduced by as much as 50%. The results vary according to the appliances used with the system. These findings have critical relevance for efforts to provide modern energy services to the 1.2 billion people worldwide without access to the electrical grid and one billion more with unreliable access. However, policy and market support are needed to realize rapid adoption of super-efficient appliances.« less

Effects of Acoustic and Fluid Dynamic Interactions in Resonators: Applications in Thermoacoustic Refrigeration

NASA Astrophysics Data System (ADS)

Antao, Dion Savio

Thermoacoustic refrigeration systems have gained increased importance in cryogenic cooling technologies and improvements are needed to increase the efficiency and effectiveness of the current cryogenic refrigeration devices. These improvements in performance require a re-examination of the fundamental acoustic and fluid dynamic interactions in the acoustic resonators that comprise a thermoacoustic refrigerator. A comprehensive research program of the pulse tube thermoacoustic refrigerator (PTR) and arbitrarily shaped, circular cross-section acoustic resonators was undertaken to develop robust computational models to design and predict the transport processes in these systems. This effort was divided into three main focus areas: (a) studying the acoustic and fluid dynamic interactions in consonant and dissonant acoustic resonators, (b) experimentally investigating thermoacoustic refrigeration systems attaining cryogenic levels and (c) computationally studying the transport processes and energy conversion through fluid-solid interactions in thermoacoustic pulse tube refrigeration devices. To investigate acoustic-fluid dynamic interactions in resonators, a high fidelity computational fluid dynamic model was developed and used to simulate the flow, pressure and temperature fields generated in consonant cylindrical and dissonant conical resonators. Excitation of the acoustic resonators produced high-amplitude standing waves in the conical resonator. The generated peak acoustic overpressures exceeded the initial undisturbed pressure by two to three times. The harmonic response in the conical resonator system was observed to be dependent on the piston amplitude. The resultant strong acoustic streaming structures in the cone resonator highlighted its potential over a cylindrical resonator as an efficient mixer. Two pulse tube cryogenic refrigeration (PTR) devices driven by a linear motor (a pressure wave generator) were designed, fabricated and tested. The characterization of the systems over a wide range of operating conditions helped to better understand the factors that govern and affect the performance of the PTR. The operating frequency of the linear motor driving the PTR affected the systems' performance the most. Other parameters that resulted in performance variations were the mean operating pressure, the pressure amplitude output from the linear motor, and the geometry of the inertance tube. The effect of the inertance tube's geometry was controlled by a single parameter labeled the "inertance". External/ambient conditions affected the performance of the cryocoolers too. To prevent the influence of the ambient conditions on the performance, a vacuum chamber was fabricated to isolate the low temperature regions of the PTR from the variable ambient atmosphere. The experiments provided important information and guidelines for the simulation studies of the PTR that were carried out concurrently. A time-dependent high fidelity computational fluid dynamic model of the entire PTR system was developed to gain a better understanding of internal interactions between the refrigerant fluid and the porous heat-exchangers in its various components and to facilitate better design of PTR systems based on the knowledge gained. The compressible forms of the conservation of mass, momentum and energy equations are solved in the gas and porous media (appropriate estimation of fluid dynamics in heat-exchangers) regions. The heat transfer in the porous regions is governed by a thermal non-equilibrium heat transfer model that calculates a separate gas and solid temperature and accounts for heat transfer between the two. The numerical model was validated using both temporal and quasi-steady state results obtained from the experimental studies. The validated model was applied to study the effects of different operating parameters (frequency, pressure and geometry of the components) on the PTR's performance. The simulations revealed interesting steady-periodic flow patterns that develop in the pulse tube due to the fluctuations caused by the piston and the presence of the inertance tube. Similar to the experiments, the simulations provided important information that help guide the design of efficient PTR systems.

MIGRATION AND GROWTH OF PROTOPLANETARY EMBRYOS. II. EMERGENCE OF PROTO-GAS-GIANT CORES VERSUS SUPER EARTH PROGENITORS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Beibei; Zhang, Xiaojia; Lin, Douglas N. C.

2015-01-01

Nearly 15%-20% of solar type stars contain one or more gas giant planets. According to the core-accretion scenario, the acquisition of their gaseous envelope must be preceded by the formation of super-critical cores with masses 10 times or larger than that of the Earth. It is natural to link the formation probability of gas giant planets with the supply of gases and solids in their natal disks. However, a much richer population of super Earths suggests that (1) there is no shortage of planetary building block material, (2) a gas giant's growth barrier is probably associated with whether it can mergemore » into super-critical cores, and (3) super Earths are probably failed cores that did not attain sufficient mass to initiate efficient accretion of gas before it is severely depleted. Here we construct a model based on the hypothesis that protoplanetary embryos migrated extensively before they were assembled into bona fide planets. We construct a Hermite-Embryo code based on a unified viscous-irradiation disk model and a prescription for the embryo-disk tidal interaction. This code is used to simulate the convergent migration of embryos, and their close encounters and coagulation. Around the progenitors of solar-type stars, the progenitor super-critical-mass cores of gas giant planets primarily form in protostellar disks with relatively high (≳ 10{sup –7} M {sub ☉} yr{sup –1}) mass accretion rates, whereas systems of super Earths (failed cores) are more likely to emerge out of natal disks with modest mass accretion rates, due to the mean motion resonance barrier and retention efficiency.« less

Investigation on the two-stage active magnetic regenerative refrigerator for liquefaction of hydrogen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Inmyong; Park, Jiho; Jeong, Sangkwon

2014-01-29

An active magnetic regenerative refrigerator (AMRR) is expected to be useful for hydrogen liquefaction due to its inherent high thermodynamic efficiency. Because the temperature of the cold end of the refrigerator has to be approximately liquid temperature, a large temperature span of the active magnetic regenerator (AMR) is indispensable when the heat sink temperature is liquid nitrogen temperature or higher. Since magnetic refrigerants are only effective in the vicinity of their own transition temperatures, which limit the temperature span of the AMR, an innovative structure is needed to increase the temperature span. The AMR must be a layered structure andmore » the thermophysical matching of magnetic field and flow convection effects is very important. In order to design an AMR for liquefaction of hydrogen, the implementation of multi-layered AMR with different magnetic refrigerants is explored with multi-staging. In this paper, the performance of the multi-layered AMR using four rare-earth compounds (GdNi{sub 2}, Gd{sub 0.1}Dy{sub 0.9}Ni{sub 2}, Dy{sub 0.85}Er{sub 0.15}Al{sub 2}, Dy{sub 0.5}Er{sub 0.5}Al{sub 2}) is investigated. The experimental apparatus includes two-stage active magnetic regenerator containing two different magnetic refrigerants each. A liquid nitrogen reservoir connected to the warm end of the AMR maintains the temperature of the warm end around 77 K. High-pressure helium gas is employed as a heat transfer fluid in the AMR and the maximum magnetic field of 4 T is supplied by the low temperature superconducting (LTS) magnet. The temperature span with the variation of parameters such as phase difference between magnetic field and mass flow rate of magnetic refrigerants in AMR is investigated. The maximum temperature span in the experiment is recorded as 50 K and several performance issues have been discussed in this paper.« less

In-line FINCH super resolution digital holographic fluorescence microscopy using a high efficiency transmission liquid crystal GRIN lens.

PubMed

Brooker, Gary; Siegel, Nisan; Rosen, Joseph; Hashimoto, Nobuyuki; Kurihara, Makoto; Tanabe, Ayano

2013-12-15

We report a new optical arrangement that creates high-efficiency, high-quality Fresnel incoherent correlation holography (FINCH) holograms using polarization sensitive transmission liquid crystal gradient index (TLCGRIN) diffractive lenses. In contrast, current universal practice in the field employs a reflective spatial light modulator (SLM) to separate sample and reference beams. Polarization sensitive TLCGRIN lenses enable a straight optical path, have >90% transmission efficiency, are not pixilated, and are free of many limitations of reflective SLM devices. For each sample point, two spherical beams created by a glass lens in combination with a polarization sensitive TLCGRIN lens interfere and create a hologram and resultant super resolution image.

Electrothermal energy conversion using electron gas volumetric change inside semiconductors

NASA Astrophysics Data System (ADS)

Yazawa, K.; Shakouri, A.

2016-07-01

We propose and analyze an electrothermal energy converter using volumetric changes in non-equilibrium electron gas inside semiconductors. The geometric concentration of electron gas under an electric field increases the effective pressure of the electrons, and then a barrier filters out cold electrons, acting like a valve. Nano- and micro-scale features enable hot electrons to arrive at the contact in a short enough time to avoid thermalization with the lattice. Key length and time scales, preliminary device geometry, and anticipated efficiency are estimated for electronic analogs of Otto and Brayton power generators and Joule-Thomson micro refrigerators on a chip. The power generators convert the energy of incident photons from the heat source to electrical current, and the refrigerator can reduce the temperature of electrons in a semiconductor device. The analytic calculations show that a large energy conversion efficiency or coefficient of performance may be possible.

Electrothermal energy conversion using electron gas volumetric change inside semiconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yazawa, K.; Shakouri, A.

2016-07-25

We propose and analyze an electrothermal energy converter using volumetric changes in non-equilibrium electron gas inside semiconductors. The geometric concentration of electron gas under an electric field increases the effective pressure of the electrons, and then a barrier filters out cold electrons, acting like a valve. Nano- and micro-scale features enable hot electrons to arrive at the contact in a short enough time to avoid thermalization with the lattice. Key length and time scales, preliminary device geometry, and anticipated efficiency are estimated for electronic analogs of Otto and Brayton power generators and Joule-Thomson micro refrigerators on a chip. The powermore » generators convert the energy of incident photons from the heat source to electrical current, and the refrigerator can reduce the temperature of electrons in a semiconductor device. The analytic calculations show that a large energy conversion efficiency or coefficient of performance may be possible.« less

Experimental analysis of direct-expansion ground-coupled heat pump systems

NASA Astrophysics Data System (ADS)

Mei, V. C.; Baxter, V. D.

1991-09-01

Direct-expansion ground-coil-coupled (DXGC) heat pump systems have certain energy efficiency advantages over conventional ground-coupled heat pump (GCHP) systems. Principal among these advantages are that the secondary heat transfer fluid heat exchanger and circulating pump are eliminated. While the DXGC concept can produce higher efficiencies, it also produces more system design and environmental problems (e.g., compressor starting, oil return, possible ground pollution, and more refrigerant charging). Furthermore, general design guidelines for DXGC systems are not well documented. A two-pronged approach was adopted for this study: (1) a literature survey, and (2) a laboratory study of a DXGC heat pump system with R-22 as the refrigerant, for both heating and cooling mode tests done in parallel and series tube connections. The results of each task are described in this paper. A set of general design guidelines was derived from the test results and is also presented.

Synthetic Zeolites and Other Microporous Oxide Molecular Sieves

NASA Astrophysics Data System (ADS)

Sherman, John D.

1999-03-01

Use of synthetic zeolites and other microporous oxides since 1950 has improved insulated windows, automobile air-conditioning, refrigerators, air brakes on trucks, laundry detergents, etc. Their large internal pore volumes, molecular-size pores, regularity of crystal structures, and the diverse framework chemical compositions allow "tailoring" of structure and properties. Thus, highly active and selective catalysts as well as adsorbents and ion exchangers with high capacities and selectivities were developed. In the petroleum refining and petrochemical industries, zeolites have made possible cheaper and lead-free gasoline, higher performance and lower-cost synthetic fibers and plastics, and many improvements in process efficiency and quality and in performance. Zeolites also help protect the environment by improving energy efficiency, reducing automobile exhaust and other emissions, cleaning up hazardous wastes (including the Three Mile Island nuclear power plant and other radioactive wastes), and, as specially tailored desiccants, facilitating the substitution of new refrigerants for the ozone-depleting chlorofluorocarbons banned by the Montreal Protocol.

Total Thermal Management of Battery Electric Vehicles (BEVs)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lustbader, Jason A; Rugh, John P; Winkler, Jonathan M

The key hurdles to achieving wide consumer acceptance of battery electric vehicles (BEVs) are weather-dependent drive range, higher cost, and limited battery life. These translate into a strong need to reduce a significant energy drain and resulting drive range loss due to auxiliary electrical loads the predominant of which is the cabin thermal management load. Studies have shown that thermal subsystem loads can reduce the drive range by as much as 45% under ambient temperatures below -10 degrees C. Often, cabin heating relies purely on positive temperature coefficient (PTC) resistive heating, contributing to a significant range loss. Reducing this rangemore » loss may improve consumer acceptance of BEVs. The authors present a unified thermal management system (UTEMPRA) that satisfies diverse thermal and design needs of the auxiliary loads in BEVs. Demonstrated on a 2015 Fiat 500e BEV, this system integrates a semi-hermetic refrigeration loop with a coolant network and serves three functions: (1) heating and/or cooling vehicle traction components (battery, power electronics, and motor) (2) heating and cooling of the cabin, and (3) waste energy harvesting and re-use. The modes of operation allow a heat pump and air conditioning system to function without reversing the refrigeration cycle to improve thermal efficiency. The refrigeration loop consists of an electric compressor, a thermal expansion valve, a coolant-cooled condenser, and a chiller, the latter two exchanging heat with hot and cold coolant streams that may be directed to various components of the thermal system. The coolant-based heat distribution is adaptable and saves significant amounts of refrigerant per vehicle. Also, a coolant-based system reduces refrigerant emissions by requiring fewer refrigerant pipe joints. The authors present bench-level test data and simulation analysis and describe a preliminary control scheme for this system.« less

A Simulink Library of cryogenic components to automatically generate control schemes for large Cryorefrigerators

NASA Astrophysics Data System (ADS)

Bonne, François; Alamir, Mazen; Hoa, Christine; Bonnay, Patrick; Bon-Mardion, Michel; Monteiro, Lionel

2015-12-01

In this article, we present a new Simulink library of cryogenics components (such as valve, phase separator, mixer, heat exchanger...) to assemble to generate model-based control schemes. Every component is described by its algebraic or differential equation and can be assembled with others to build the dynamical model of a complete refrigerator or the model of a subpart of it. The obtained model can be used to automatically design advanced model based control scheme. It also can be used to design a model based PI controller. Advanced control schemes aim to replace classical user experience designed approaches usually based on many independent PI controllers. This is particularly useful in the case where cryoplants are submitted to large pulsed thermal loads, expected to take place in future fusion reactors such as those expected in the cryogenic cooling systems of the International Thermonuclear Experimental Reactor (ITER) or the Japan Torus-60 Super Advanced Fusion Experiment (JT- 60SA). The paper gives the example of the generation of the dynamical model of the 400W@1.8K refrigerator and shows how to build a Constrained Model Predictive Control for it. Based on the scheme, experimental results will be given. This work is being supported by the French national research agency (ANR) through the ANR-13-SEED-0005 CRYOGREEN program.

Magnetic Heat Pump Containing Flow Diverters

NASA Technical Reports Server (NTRS)

Howard, Frank S.

1995-01-01

Proposed magnetic heat pump contains flow diverters for suppression of undesired flows. If left unchecked, undesired flows mix substantial amounts of partially heated and partially cooled portions of working fluid, effectively causing leakage of heat from heated side to cooled side. By reducing leakage of heat, flow diverters increase energy efficiency of magnetic heat pump, potentially offering efficiency greater than compressor-driven refrigerator.

Super: a web server to rapidly screen superposable oligopeptide fragments from the protein data bank

PubMed Central

Collier, James H.; Lesk, Arthur M.; Garcia de la Banda, Maria; Konagurthu, Arun S.

2012-01-01

Searching for well-fitting 3D oligopeptide fragments within a large collection of protein structures is an important task central to many analyses involving protein structures. This article reports a new web server, Super, dedicated to the task of rapidly screening the protein data bank (PDB) to identify all fragments that superpose with a query under a prespecified threshold of root-mean-square deviation (RMSD). Super relies on efficiently computing a mathematical bound on the commonly used structural similarity measure, RMSD of superposition. This allows the server to filter out a large proportion of fragments that are unrelated to the query; >99% of the total number of fragments in some cases. For a typical query, Super scans the current PDB containing over 80 500 structures (with ∼40 million potential oligopeptide fragments to match) in under a minute. Super web server is freely accessible from: http://lcb.infotech.monash.edu.au/super. PMID:22638586

Exergy analysis of large-scale helium liquefiers: Evaluating design trade-offs

NASA Astrophysics Data System (ADS)

Thomas, Rijo Jacob; Ghosh, Parthasarathi; Chowdhury, Kanchan

2014-01-01

It is known that higher heat exchanger area, more number of expanders with higher efficiency and more involved configuration with multi-pressure compression system increase the plant efficiency of a helium liquefier. However, they involve higher capital investment and larger size. Using simulation software Aspen Hysys v 7.0 and exergy analysis as the tool of analysis, authors have attempted to identify various trade-offs while selecting the number of stages, the pressure levels in compressor, the cold-end configuration, the heat exchanger surface area, the maximum allowable pressure drop in heat exchangers, the efficiency of expanders, the parallel/series connection of expanders etc. Use of more efficient cold ends reduces the number of refrigeration stages and the size of the plant. For achieving reliability along with performance, a configuration with a combination of expander and Joule-Thomson valve is found to be a better choice for cold end. Use of multi-pressure system is relevant only when the number of refrigeration stages is more than 5. Arrangement of expanders in series reduces the number of expanders as well as the heat exchanger size with slight expense of plant efficiency. Superior heat exchanger (having less pressure drop per unit heat transfer area) results in only 5% increase of plant performance even when it has 100% higher heat exchanger surface area.

Nitrogen source effects on nitrous oxide emissions from irrigated no-till corn.

PubMed

Halvorson, Ardell D; Del Grosso, Stephen J; Francesco, Alluvione

2010-01-01

Nitrogen fertilization is essential for optimizing crop yields; however, it may potentially increase nitrous oxide (N2O) emissions. The study objective was to assess the ability of commercially available enhanced-efficiency N fertilizers to reduce N2O emissions following their application in comparison with conventional dry granular urea and liquid urea-ammonium nitrate (UAN) fertilizers in an irrigated no-till (NT) corn (Zea mays L.) production system. Four enhanced-efficiency fertilizers were evaluated: two polymer-coated urea products (ESN and Duration III) and two fertilizers containing nitrification and urease inhibitors (SuperU and UAN+AgrotainPlus). Nitrous oxide fluxes were measured during two growing seasons using static, vented chambers and a gas chromatograph analyzer. Enhanced-efficiency fertilizers significantly reduced growing-season N2O-N emissions in comparison with urea, including UAN. SuperU and UAN+AgrotainPlus had significantly lower N2O-N emissions than UAN. Compared with urea, SuperU reduced N2O-N emissions 48%, ESN 34%, Duration III 31%, UAN 27%, and UAN+AgrotainPlus 53% averaged over 2 yr. Compared with UAN, UAN+AgrotainPlus reduced N2O emissions 35% and SuperU 29% averaged over 2 yr. The N2O-N loss as a percentage of N applied was 0.3% for urea, with all other N sources having significantly lower losses. Grain production was not reduced by the use of alternative N sources. This work shows that enhanced-efficiency N fertilizers can potentially reduce N2O-N emissions without affecting yields from irrigated NT corn systems in the semiarid central Great Plains.

Effect of thermal annealing Super Yellow emissive layer on efficiency of OLEDs

PubMed Central

Burns, Samantha; MacLeod, Jennifer; Trang Do, Thu; Sonar, Prashant; Yambem, Soniya D.

2017-01-01

Thermal annealing of the emissive layer of an organic light emitting diode (OLED) is a common practice for solution processable emissive layers and reported annealing temperatures varies across a wide range of temperatures. We have investigated the influence of thermal annealing of the emissive layer at different temperatures on the performance of OLEDs. Solution processed polymer Super Yellow emissive layers were annealed at different temperatures and their performances were compared against OLEDs with a non-annealed emissive layer. We found a significant difference in the efficiency of OLEDs with different annealing temperatures. The external quantum efficiency (EQE) reached a maximum of 4.09% with the emissive layer annealed at 50 °C. The EQE dropped by ~35% (to 2.72%) for OLEDs with the emissive layers annealed at 200 °C. The observed performances of OLEDs were found to be closely related to thermal properties of polymer Super Yellow. The results reported here provide an important guideline for processing emissive layers and are significant for OLED and other organic electronics research communities. PMID:28106082

Absorption machine with desorber-resorber

DOEpatents

Biermann, Wendell J.

1985-01-01

An absorption refrigeration system utilizing a low temperature desorber and intermediate temperature resorber. The system operates at three temperatures and three pressures to increase the efficiency of the system and is capable of utilizing a lower generator temperature than previously used.

ENERGY STAR Certified Vending Machines

EPA Pesticide Factsheets

Certified models meet all ENERGY STAR requirements as listed in the Version 3.0 ENERGY STAR Program Requirements for Refrigerated Beverage Vending Machines that are effective as of March 1, 2013. A detailed listing of key efficiency criteria are available at

Apparatus and method for evaporator defrosting

DOEpatents

Mei, Viung C.; Chen, Fang C.; Domitrovic, Ronald E.

2001-01-01

An apparatus and method for warm-liquid defrosting of the evaporator of a refrigeration system. The apparatus includes a first refrigerant expansion device that selectively expands refrigerant for cooling the evaporator, a second refrigerant expansion device that selectively expands the refrigerant after the refrigerant has passed through the evaporator, and a defrosting control for the first refrigerant expansion device and second refrigerant expansion device to selectively defrost the evaporator by causing warm refrigerant to flow through the evaporator. The apparatus is alternately embodied with a first refrigerant bypass and/or a second refrigerant bypass for selectively directing refrigerant to respectively bypass the first refrigerant expansion device and the second refrigerant expansion device, and with the defrosting control connected to the first refrigerant bypass and/or the second refrigerant bypass to selectively activate and deactivate the bypasses depending upon the current cycle of the refrigeration system. The apparatus alternately includes an accumulator for accumulating liquid and/or gaseous refrigerant that is then pumped either to a refrigerant receiver or the first refrigerant expansion device for enhanced evaporator defrosting capability. The inventive method of defrosting an evaporator in a refrigeration system includes the steps of compressing refrigerant in a compressor and cooling the refrigerant in the condenser such that the refrigerant is substantially in liquid form, passing the refrigerant substantially in liquid form through the evaporator, and expanding the refrigerant with a refrigerant expansion device after the refrigerant substantially passes through the evaporator.

The internal architecture of dendritic spines revealed by super-resolution imaging: What did we learn so far?

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacGillavry, Harold D., E-mail: h.d.macgillavry@uu.nl; Hoogenraad, Casper C., E-mail: c.hoogenraad@uu.nl

2015-07-15

The molecular architecture of dendritic spines defines the efficiency of signal transmission across excitatory synapses. It is therefore critical to understand the mechanisms that control the dynamic localization of the molecular constituents within spines. However, because of the small scale at which most processes within spines take place, conventional light microscopy techniques are not adequate to provide the necessary level of resolution. Recently, super-resolution imaging techniques have overcome the classical barrier imposed by the diffraction of light, and can now resolve the localization and dynamic behavior of proteins within small compartments with nanometer precision, revolutionizing the study of dendritic spinemore » architecture. Here, we highlight exciting new findings from recent super-resolution studies on neuronal spines, and discuss how these studies revealed important new insights into how protein complexes are assembled and how their dynamic behavior shapes the efficiency of synaptic transmission.« less

Super-resolution photon-efficient imaging by nanometric double-helix point spread function localization of emitters (SPINDLE)

PubMed Central

Grover, Ginni; DeLuca, Keith; Quirin, Sean; DeLuca, Jennifer; Piestun, Rafael

2012-01-01

Super-resolution imaging with photo-activatable or photo-switchable probes is a promising tool in biological applications to reveal previously unresolved intra-cellular details with visible light. This field benefits from developments in the areas of molecular probes, optical systems, and computational post-processing of the data. The joint design of optics and reconstruction processes using double-helix point spread functions (DH-PSF) provides high resolution three-dimensional (3D) imaging over a long depth-of-field. We demonstrate for the first time a method integrating a Fisher information efficient DH-PSF design, a surface relief optical phase mask, and an optimal 3D localization estimator. 3D super-resolution imaging using photo-switchable dyes reveals the 3D microtubule network in mammalian cells with localization precision approaching the information theoretical limit over a depth of 1.2 µm. PMID:23187521

Research on laser detonation pulse circuit with low-power based on super capacitor

NASA Astrophysics Data System (ADS)

Wang, Hao-yu; Hong, Jin; He, Aifeng; Jing, Bo; Cao, Chun-qiang; Ma, Yue; Chu, En-yi; Hu, Ya-dong

2018-03-01

According to the demand of laser initiating device miniaturization and low power consumption of weapon system, research on the low power pulse laser detonation circuit with super capacitor. Established a dynamic model of laser output based on super capacitance storage capacity, discharge voltage and programmable output pulse width. The output performance of the super capacitor under different energy storage capacity and discharge voltage is obtained by simulation. The experimental test system was set up, and the laser diode of low power pulsed laser detonation circuit was tested and the laser output waveform of laser diode in different energy storage capacity and discharge voltage was collected. Experiments show that low power pulse laser detonation based on super capacitor energy storage circuit discharge with high efficiency, good transient performance, for a low power consumption requirement, for laser detonation system and low power consumption and provide reference light miniaturization of engineering practice.

Turing pattern dynamics and adaptive discretization for a super-diffusive Lotka-Volterra model.

PubMed

Bendahmane, Mostafa; Ruiz-Baier, Ricardo; Tian, Canrong

2016-05-01

In this paper we analyze the effects of introducing the fractional-in-space operator into a Lotka-Volterra competitive model describing population super-diffusion. First, we study how cross super-diffusion influences the formation of spatial patterns: a linear stability analysis is carried out, showing that cross super-diffusion triggers Turing instabilities, whereas classical (self) super-diffusion does not. In addition we perform a weakly nonlinear analysis yielding a system of amplitude equations, whose study shows the stability of Turing steady states. A second goal of this contribution is to propose a fully adaptive multiresolution finite volume method that employs shifted Grünwald gradient approximations, and which is tailored for a larger class of systems involving fractional diffusion operators. The scheme is aimed at efficient dynamic mesh adaptation and substantial savings in computational burden. A numerical simulation of the model was performed near the instability boundaries, confirming the behavior predicted by our analysis.

120 Hz pulse tube cryocooler for fast cooldown to 50 K

NASA Astrophysics Data System (ADS)

Vanapalli, Srinivas; Lewis, Michael; Gan, Zhihua; Radebaugh, Ray

2007-02-01

A pulse tube cryocooler operating at 120Hz with 3.5MPa average pressure achieved a no-load temperature of about 49.9K and a cooldown time to 80K of 5.5min. The net refrigeration power at 80K was 3.35W with an efficiency of 19.7% of Carnot when referred to input pressure-volume (PV or acoustic) power. Such low temperatures have not been previously achieved for operating frequencies above 100Hz. The high frequency operation leads to reduced cryocooler volume for a given refrigeration power, which is important to many applications and can enable development of microcryocoolers for microelectromechanical system applications.

Energy conservation in ice skating rinks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dietrich, B.K.; McAvoy, T.J.

1980-01-01

An economic and energy analysis of ice rinks was made to examine the areas in which energy could be profitably conserved. The areas where new equipment could make a major reduction in energy use are: the use of waste heat for space heating, the installation of a low emissivity false ceiling to reduce radiant heat, the use of a load cycling controller to reduce refrigeration costs, and the installation of more efficient lighting systems. Changes in rink operating procedure that could cut energy use are: higher refrigerant temperatures, thinner ice, the use of colder resurfacing water, turning the compressors andmore » pumps off at night, and reducing ventilation.« less

Optical microscope and tapered fiber coupling apparatus for a dilution refrigerator.

PubMed

MacDonald, A J R; Popowich, G G; Hauer, B D; Kim, P H; Fredrick, A; Rojas, X; Doolin, P; Davis, J P

2015-01-01

We have developed a system for tapered fiber measurements of optomechanical resonators inside a dilution refrigerator, which is compatible with both on- and off-chip devices. Our apparatus features full three-dimensional control of the taper-resonator coupling conditions enabling critical coupling, with an overall fiber transmission efficiency of up to 70%. Notably, our design incorporates an optical microscope system consisting of a coherent bundle of 37,000 optical fibers for real-time imaging of the experiment at a resolution of ∼1 μm. We present cryogenic optical and optomechanical measurements of resonators coupled to tapered fibers at temperatures as low as 9 mK.

An experimental study of cutting performances in machining of nimonic super alloy GH2312

NASA Astrophysics Data System (ADS)

Du, Jinfu; Wang, Xi; Xu, Min; Mao, Jin; Zhao, Xinglong

2018-05-01

Nimonic super alloy are extensively used in the aerospace industry because of its unique properties. As they are quite costly and difficult to machine, the machining tool is easy to get worn. To solve the problem, an experiment was carried out on a numerical control slitting automatic lathe to analysis the tool wearing conditions and parts' surface quality of nimonic super alloy GH2132 under different cutters. The selection of suitable cutter, reasonable cutting data and cutting speed is obtained and some conclusions are made. The excellent coating tool, compared with other hard alloy cutters, along with suitable cutting data will greatly improve the production efficiency and product quality, it can completely meet the process of nimonic super alloy GH2312.

In situ growth of hierarchical Al2O3 nanostructures onto TiO2 nanofibers surface: super-hydrophilicity, efficient oil/water separation and dye-removal.

PubMed

Fu, Wanlin; Dai, Yunqian; Tian, Jilan; Huang, Chaobo; Liu, Zhongche; Liu, Ken; Yin, Linzhi; Huang, Fangfang; Lu, Yingwei; Sun, Yueming

2018-08-24

Developing a facile strategy to synthesize template-free TiO 2 membrane with stable super-hydrophilic surface is still a daunting challenge. In this work, super-hydrophilicity (close to 0°) and underwater super-oleophobicity (165°) have been successfully demonstrated on a hierarchical Al 2 O 3 /TiO 2 membrane, which is prepared via a facile electrospinning method followed by simple calcination in air. The precisely-tuned Al 2 O 3 heterojunctions grew in situ and dispersed uniformly on the TiO 2 surface, resulting in an 'island in the sea' configuration. Such a unique feature allows not only achieving super-hydrophilicity by maximizing the surface roughness and enhancing the hydrogen bonding, but also improving the adsorption capacity toward different toxic dyes utilizing the abundant adsorption sites protected by the hierarchical nanostructure during sintering. The new Al 2 O 3 /TiO 2 nanofibrous membrane can serve as a novel filter for gravity driven oil/water separation along with dye removal, achieving 97.7% of oil/water separation efficiency and 98% of dye capture, thanks to their superb wettability and the sophisticated adsorptive performance. Our presented fabrication strategy can be extended to a wide range of ceramic materials and inspires their advanced applications in water purification under harsh liquid-phase environments.

Lubrication free centrifugal compressor. Technical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gottschlich, J.M.; Scaringe, R.P.; Gui, F.

1994-04-22

This paper describes an effort to demonstrate the benefits of an innovative, lightweight, lubrication free centrifugal compressor that allows the use of environmentally sale alternate refrigerants with improved system efficiencies over current state-of-the-art technology. This effort couples the recently developed 3-D high efficiency centrifugal compressor and fabrication technologies with magnetic bearing technology and will then prove the performance, life and reliability of the compressor.

Melting in super-earths.

PubMed

Stixrude, Lars

2014-04-28

We examine the possible extent of melting in rock-iron super-earths, focusing on those in the habitable zone. We consider the energetics of accretion and core formation, the timescale of cooling and its dependence on viscosity and partial melting, thermal regulation via the temperature dependence of viscosity, and the melting curves of rock and iron components at the ultra-high pressures characteristic of super-earths. We find that the efficiency of kinetic energy deposition during accretion increases with planetary mass; considering the likely role of giant impacts and core formation, we find that super-earths probably complete their accretionary phase in an entirely molten state. Considerations of thermal regulation lead us to propose model temperature profiles of super-earths that are controlled by silicate melting. We estimate melting curves of iron and rock components up to the extreme pressures characteristic of super-earth interiors based on existing experimental and ab initio results and scaling laws. We construct super-earth thermal models by solving the equations of mass conservation and hydrostatic equilibrium, together with equations of state of rock and iron components. We set the potential temperature at the core-mantle boundary and at the surface to the local silicate melting temperature. We find that ancient (∼4 Gyr) super-earths may be partially molten at the top and bottom of their mantles, and that mantle convection is sufficiently vigorous to sustain dynamo action over the whole range of super-earth masses.

Heat-driven thermoacoustic cryocooler operating at liquid hydrogen temperature with a unique coupler

NASA Astrophysics Data System (ADS)

Hu, J. Y.; Luo, E. C.; Li, S. F.; Yu, B.; Dai, W.

2008-05-01

A heat-driven thermoacoustic cryocooler is constructed. A unique coupler composed of a tube, reservoir, and elastic diaphragm is introduced to couple a traveling-wave thermoacoustic engine (TE) and two-stage pulse tube refrigerator (PTR). The amplitude of the pressure wave generated in the engine is first amplified in the coupler and the wave then passes into the refrigerator to pump heat. The TE uses nitrogen as its working gas and the PTR still uses helium as its working gas. With this coupler, the efficiency of the system is doubled. The engine and coupler match at a much lower operating frequency, which is of great benefit for the PTR to obtain a lower cooling temperature. The coupling place between the coupler and engine is also optimized. The onset problem is effectively solved. With these improvements, the heat-driven thermoacoustic cryocooler reaches a lowest temperature of 18.1K, which is the demonstration of heat-driven thermoacoustic refrigeration technology used for cooling at liquid hydrogen temperatures.

Cycle Design of Reverse Brayton Cryocooler for HTS Cable Cooling Using Exergy Analysis

NASA Astrophysics Data System (ADS)

Gupta, Sudeep Kumar; Ghosh, Parthasarathi

2017-02-01

The reliability and price of cryogenic refrigeration play an important role in the successful commercialization of High Temperature Superconducting (HTS) cables. For cooling HTS cable, sub-cooled liquid nitrogen (LN2) circulation system is used. One of the options to maintain LN2 in its sub-cooled state is by providing refrigeration with the help of Reverse Brayton Cryo-cooler (RBC). The refrigeration requirement is 10 kW for continuously sub-cooling LN2 from 72 K to 65 K for cooling 1 km length of HTS cable [1]. In this paper, a parametric evaluation of RBC for sub-cooling LN2 has been performed using helium as a process fluid. Exergy approach has been adopted for this analysis. A commercial process simulator, Aspen HYSYS® V8.6 has been used for this purpose. The critical components have been identified and their exergy destruction and exergy efficiency have been obtained for a given heat load condition.

Comparison between reverse Brayton and Kapitza based LNG boil-off gas reliquefaction system using exergy analysis

NASA Astrophysics Data System (ADS)

Kochunni, Sarun Kumar; Chowdhury, Kanchan

2017-02-01

LNG boil-off gas (BOG) reliquefaction systems in LNG carrier ships uses refrigeration devices which are based on reverse Brayton, Claude, Kapitza (modified Claude) or Cascade cycles. Some of these refrigeration devices use nitrogen as the refrigerants and hence nitrogen storage vessels or nitrogen generators needs to be installed in LNG carrier ships which consume space and add weight to the carrier. In the present work, a new configuration based on Kapitza liquefaction cycle which uses BOG itself as working fluid is proposed and has been compared with Reverse Brayton Cycle (RBC) on sizes of heat exchangers and compressor operating parameters. Exergy analysis is done after simulating at steady state with Aspen Hysys 8.6® and the comparison between RBC and Kapitza may help designers to choose reliquefaction system with appropriate process parameters and sizes of equipment. With comparable exergetic efficiency as that of an RBC, a Kaptiza system needs only BOG compressor without any need of nitrogen gas.

Optimization Strategies for Single-Stage, Multi-Stage and Continuous ADRs

NASA Technical Reports Server (NTRS)

Shirron, Peter J.

2014-01-01

Adiabatic Demagnetization Refrigerators (ADR) have many advantages that are prompting a resurgence in their use in spaceflight and laboratory applications. They are solid-state coolers capable of very high efficiency and very wide operating range. However, their low energy storage density translates to larger mass for a given cooling capacity than is possible with other refrigeration techniques. The interplay between refrigerant mass and other parameters such as magnetic field and heat transfer points in multi-stage ADRs gives rise to a wide parameter space for optimization. This paper first presents optimization strategies for single ADR stages, focusing primarily on obtaining the largest cooling capacity per stage mass, then discusses the optimization of multi-stage and continuous ADRs in the context of the coordinated heat transfer that must occur between stages. The goal for the latter is usually to obtain the largest cooling power per mass or volume, but there can also be many secondary objectives, such as limiting instantaneous heat rejection rates and producing intermediate temperatures for cooling of other instrument components.

Cascading pulse tubes on a large diaphragm pressure wave generator to increase liquefaction potential

NASA Astrophysics Data System (ADS)

Caughley, A.; Meier, J.; Nation, M.; Reynolds, H.; Boyle, C.; Tanchon, J.

2017-12-01

Fabrum Solutions, in collaboration with Absolut System and Callaghan Innovation, produce a range of large pulse tube cryocoolers based on metal diaphragm pressure wave generator technology (DPWG). The largest cryocooler consists of three in-line pulse tubes working in parallel on a 1000 cm3 swept volume DPWG. It has demonstrated 1280 W of refrigeration at 77 K, from 24 kW of input power and was subsequently incorporated into a liquefaction plant to produce liquid nitrogen for an industrial customer. The pulse tubes on the large cryocooler each produced 426 W of refrigeration at 77 K. However, pulse tubes can produce more refrigeration with higher efficiency at higher temperatures. This paper presents the results from experiments to increase overall liquefaction throughput by operating one or more pulse tubes at a higher temperature to pre-cool the incoming gas. The experiments showed that the effective cooling increased to 1500 W resulting in an increase in liquefaction rate from 13 to 16 l/hour.

The development of a performance-enhancing additive for vapor-compression heat pumps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grzyll, L.R.; Scaringe, R.P.; Gottschlich, J.M.

1997-12-31

This paper describes the testing results of a vapor-compression heat pump operating with HFC-134a refrigerant and a performance-enhancing additive. Preliminary bench-top testing of this additive, when added to polyolester (POE) lubricant and HFC-134a refrigerant, showed surprising enhancements to system COP. To further investigate this finding, the authors designed and fabricated a vapor-compression heat pump test stand for the 3--5 ton range. The authors investigated the effect of different concentrations of this additive on various system performance parameters such as cooling capacity, compressor power requirement, pressure ratio, compressor pressure difference, compressor isentropic efficiency, refrigerant flow rate, and heat exchanger performance. Themore » authors investigated various heat source and heat sink conditions to simulate air-conditioning and heat pump operating conditions. To investigate the effect of this additive on compressor lubrication and life, the authors performed compressor life tests (with scroll and reciprocating compressors), and had lubrication wear tests performed with various concentrations of the additive in the POE lubricant.« less

Development of a 25 K Pulse Tube Refrigerator for Future HTS-Series Products in Power Engineering

NASA Astrophysics Data System (ADS)

Gromoll, B.; Huber, N.; Dietrich, M.; Yang, L. W.; Thummes, G.

2006-04-01

Demands are made on refrigerators for future HTS-series products like generators, motors, transformers, which are only partly fulfilled by commercially available refrigerators. Based on the experiences with HTS-prototypes, pulse tube refrigerators (PTRs) are considered to have the highest potential to fulfill the identified requirements. Siemens have therefore started the development of a high-performance PTR together with TransMIT Giessen. Design target is a PTR with a cooling power of 80 W near 25 K based on an oil-free CFIC — linear compressor with a power input of 2 × 5 kW. The initial tests on the first single-stage laboratory version of this PTR with stainless steel mesh regenerator revealed high regenerator losses from circulating mass flow that manifests itself in form of an azimuthal temperature asymmetry in the regenerator. The circulating flow can be greatly reduced by increasing the transverse heat conductance of the matrix by use of stacks of different materials. So far, the minimum no-load temperature of the PTR is 35 K and a cooling power of 75 W is available at 50 K with a compressor efficiency of about 80 %. Further optimization of the regenerator matrix appears to be possible.

Effect of Feed Gas Flow Rate on CO2 Absorption through Super Hydrophobic Hollow Fiber membrane Contactor

NASA Astrophysics Data System (ADS)

Kartohardjono, Sutrasno; Alexander, Kevin; Larasati, Annisa; Sihombing, Ivander Christian

2018-03-01

Carbon dioxide is pollutant in natural gas that could reduce the heating value of the natural gas and cause problem in transportation due to corrosive to the pipeline. This study aims to evaluate the effects of feed gas flow rate on CO2 absorption through super hydrophobic hollow fiber contactor. Polyethyleneglycol-300 (PEG-300) solution was used as absorbent in this study, whilst the feed gas used in the experiment was a mixture of 30% CO2 and 70% CH4. There are three super hydrophobic hollow fiber contactors sized 6 cm and 25 cm in diameter and length used in this study, which consists of 1000, 3000 and 5000 fibers, respectively. The super hydrophobic fiber membrane used is polypropylene-based with outer and inner diameter of about 525 and 235 μm, respectively. In the experiments, the feed gas was sent through the shell side of the membrane contactor, whilst the absorbent solution was pumped through the lumen fibers. The experimental results showed that the mass transfer coefficient, flux, absorption efficiency for CO2-N2 system and CO2 loading increased with the feed gas flow rate, but the absorption efficiency for CO2-N2 system decreased. The mass transfer coefficient and the flux, at the same feed gas flow rate, decreased with the number of fibers in the membrane contactor, but the CO2 absorption efficiency and the CO2 loading increased.

Recovery Act--Class 8 Truck Freight Efficiency Improvement Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trucks, Daimler

2015-07-26

Daimler Trucks North America completed a five year, $79.6M project to develop and demonstrate a concept vehicle with at least 50% freight efficiency improvement over a weighted average of several drive cycles relative to a 2009 best-in-class baseline vehicle. DTNA chose a very fuel efficient baseline vehicle, the 2009 Freightliner Cascadia with a DD15 engine, yet successfully demonstrated a 115% freight efficiency improvement. DTNA learned a great deal about the various technologies that were incorporated into Super Truck and those that, through down-selection, were discarded. Some of the technologies competed with each other for efficiency, and notably some of themore » technologies complemented each other. For example, we found that Super Truck’s improved aerodynamic drag resulted in improved fuel savings from eCoast, relative to a similar vehicle with worse aerodynamic drag. However, some technologies were in direct competition with each other, namely the predictive technologies which use GPS and 3D digital maps to efficiently manage the vehicles kinetic energy through controls and software, versus hybrid which is a much costlier technology that essentially targets the same inefficiency. Furthermore, the benefits of a comprehensive, integrated powertrain/vehicle approach was proven, in which vast improvements in vehicle efficiency (e.g. lower aero drag and driveline losses) enabled engine strategies such as downrating and downspeeding. The joint engine and vehicle developments proved to be a multiplier-effect which resulted in large freight efficiency improvements. Although a large number of technologies made the selection process and were used on the Super Truck demonstrator vehicle, some of the technologies proved not feasible for series production.« less

Optimal Power and Efficiency of Quantum Thermoacoustic Micro-cycle Working in 1D Harmonic Trap

NASA Astrophysics Data System (ADS)

E, Qing; Wu, Feng; Yin, Yong; Liu, XiaoWei

2017-10-01

Thermoacoustic engines (including heat engines and refrigerators) are energy conversion devices without moving part. They have great potential in aviation, new energy utilization, power technology, refrigerating and cryogenics. The thermoacoustic parcels, which compose the working fluid of a thermoacoustic engine, oscillate within the sound channel with a temperature gradient. The thermodynamic foundation of a thermoacoustic engine is the thermoacoustic micro-cycle (TAMC). In this paper, the theory of quantum mechanics is applied to the study of the actual thermoacoustic micro-cycle for the first time. A quantum mechanics model of the TAMC working in a 1D harmonic trap, which is named as a quantum thermoacoustic micro-cycle (QTAMC), is established. The QTAMC is composed of two constant force processes connected by two straight line processes. Analytic expressions of the power output and the efficiency for QTAMC have been derived. The effects of the trap width and the temperature amplitude on the power output and the thermal efficiency have been discussed. Some optimal characteristic curves of power output versus efficiency are plotted, and then the optimization region of QTAMC is given in this paper. The results obtained here not only enrich the thermoacoustic theory but also expand the application of quantum thermodynamics.

Influence of thermophysical properties of working fluid on the design of cryogenic turboexpanders using nsds diagram

NASA Astrophysics Data System (ADS)

Sam, Ashish A.; Ghosh, Parthasarathi

2015-12-01

Cryogenic turboexpanders are an essential part of liquefaction and refrigeration plants. The thermodynamic efficiency of these plants depends upon the efficiency of the turboexpander, which is the main cold generating component of these plants, and therefore, they should be designed for high thermodynamic efficiencies. Balje's [1] nsdschart, which is a contour of isentropic efficiencies plotted against specific speed and specific diameter, is commonly used for the preliminary design of cryogenic turboexpanders. But, these charts were developed based on calculations for a specific heat ratio (γ) of 1.4, and studies show that care should be taken while implementing the same for gases which have a higher γ of 1.67. Hence there is a need to investigate the extent of applicability of nsds diagram in designing expansion turbines for higher specific heat ratios. In this paper, Computational Fluid Dynamics (CFD) analysis of cryogenic turboexpanders was carried out using Ansys CFX®. The turboexpanders were designed based on the methodologies prescribed by Kun and Sentz [2] following the nsds diagram of Balje and Hasselgruber's technique for generating blade profile. The computational results of the two cases were analysed to investigate the applicability of Balje's nsds diagram for the design of turboexpanders for refrigeration and liquefaction cycles.

Teaching Ionic Solvation Structure with a Monte Carlo Liquid Simulation Program

ERIC Educational Resources Information Center

Serrano, Agostinho; Santos, Flavia M. T.; Greca, Ileana M.

2004-01-01

The use of molecular dynamics and Monte Carlo methods has provided efficient means to stimulate the behavior of molecular liquids and solutions. A Monte Carlo simulation program is used to compute the structure of liquid water and of water as a solvent to Na(super +), Cl(super -), and Ar on a personal computer to show that it is easily feasible to…

A multipurpose information engine that can go beyond the Carnot limit

NASA Astrophysics Data System (ADS)

Rana, Shubhashis; Jayannavar, A. M.

2016-10-01

Motivated by the recent work of Mandal and Jarzynski on an autonomous Maxwell demon information engine, we have extended their model by introducing two different heat baths. The system (demon) is coupled to a memory register (tape) and a work source. The performance of the system depends on the interplay between the two sources along with the heat baths. We have found that the system can act as an engine, refrigerator or an eraser. Even the combination of any two is possible in some parameter space. We have achieved an efficiency of the engine greater than the Carnot limit. The coefficient of performance of the refrigerator is also larger than the Carnot limit.

Three-stage sorption type cryogenic refrigeration systems and methods employing heat regeneration

NASA Technical Reports Server (NTRS)

Bard, Steven (Inventor); Jones, Jack A. (Inventor)

1992-01-01

A three-stage sorption type cryogenic refrigeration system, each stage containing a fluid having a respectively different boiling point, is presented. Each stage includes a compressor in which a respective fluid is heated to be placed in a high pressure gaseous state. The compressor for that fluid which is heated to the highest temperature is enclosed by the other two compressors to permit heat to be transferred from the inner compressor to the surrounding compressors. The system may include two sets of compressors, each having the structure described above, with the interior compressors of the two sets coupled together to permit selective heat transfer therebetween, resulting in more efficient utilization of input power.

Research and Development Opportunities for Joining Technologies in HVAC&R

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goetzler, William; Guernsey, Matt; Young, Jim

The Building Technologies Office (BTO) works with researchers and industry partners to develop and deploy technologies that can substantially reduce energy consumption and greenhouse gas (GHG) emissions in residential and commercial buildings. This opportunity assessment aims to advance BTO’s energy savings, GHG reduction, and other program goals by identifying research and development (R&D) initiatives for joining technologies in heating, ventilation, air-conditioning, and refrigeration (HVAC&R) systems. Improving joining technologies for HVAC&R equipment has the potential to increase lifetime equipment operating efficiency, decrease equipment and project cost, and most importantly reduce hydroflourocarbon (HFC) refrigerant leakage to support HFC phasedown and GHG reductionmore » goals.« less

Giant magnetocaloric effect in melt-spun Ni-Mn-Ga ribbons with magneto-multistructural transformation

NASA Astrophysics Data System (ADS)

Li, Zongbin; Zhang, Yudong; Sánchez-Valdés, C. F.; Sánchez Llamazares, J. L.; Esling, Claude; Zhao, Xiang; Zuo, Liang

2014-01-01

Magnetic refrigeration based on the magnetocaloric effect (MCE) may provide an energy-efficient and environment-friendly alternative to the conventional gas compression/expansion cooling technology. For potential applications, low-cost and high-performance magnetic refrigerants are in great need. Here, we demonstrate that giant MCE can be achieved in annealed Ni52Mn26Ga22 ribbons with magneto-multistructural transformation. It yields a maximum magnetic entropy change of -30.0 J kg-1 K-1 at the magnetic field change of 5 T, being almost three times as that of initial melt-spun ribbons and comparable to or even superior to that of polycrystalline bulk alloys.

Water-Assisted Highly Efficient Synthesis of Impurity-Free Single-Walled Carbon Nanotubes-``Super-Growth''

NASA Astrophysics Data System (ADS)

Hata, Kenji

2005-03-01

We demonstrate an extremely efficient chemical vapour deposition synthesis of single-walled carbon nanotubes where the activity and lifetime of the catalysts are enhanced by water [1]. Water-stimulated enhanced catalytic activity results in massive growth of super-dense and vertically-aligned nanotube forests with heights up to 2.5 millimeters that can be easily separated from the catalysts, providing nanotube material with carbon purity above 99.98%. Moreover, patterned highly organized intrinsic nanotube structures were successfully fabricated. The water-assisted synthesis method addresses many critical problems that currently plague carbon nanotube synthesis. [1] K. Hata, et al., Science, 306, 1362 (2004).

Super-AGB Stars and their Role as Electron Capture Supernova Progenitors

NASA Astrophysics Data System (ADS)

Doherty, Carolyn L.; Gil-Pons, Pilar; Siess, Lionel; Lattanzio, John C.

2017-11-01

We review the lives, deaths and nucleosynthetic signatures of intermediate-mass stars in the range ≈6-12 M⊙, which form super-AGB stars near the end of their lives. The critical mass boundaries both between different types of massive white dwarfs (CO, CO-Ne, ONe), and between white dwarfs and supernovae, are examined along with the relative fraction of super-AGB stars that end life either as an ONe white dwarf or as a neutron star (or an ONeFe white dwarf), after undergoing an electron capture supernova event. The contribution of the other potential single-star channel to electron-capture supernovae, that of the failed massive stars, is also discussed. The factors that influence these different final fates and mass limits, such as composition, rotation, the efficiency of convection, the nuclear reaction rates, mass-loss rates, and third dredge-up efficiency, are described. We stress the importance of the binary evolution channels for producing electron-capture supernovae. Recent nucleosynthesis calculations and elemental yield results are discussed and a new set of s-process heavy element yields is presented. The contribution of super-AGB star nucleosynthesis is assessed within a Galactic perspective, and the (super-)AGB scenario is considered in the context of the multiple stellar populations seen in globular clusters. A brief summary of recent works on dust production is included. Last, we conclude with a discussion of the observational constraints and potential future advances for study into these stars on the low mass/high mass star boundary.

Portable refrigerant charge meter and method for determining the actual refrigerant charge in HVAC systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Zhiming; Abdelaziz, Omar; LaClair, Tim L.

A refrigerant charge meter and a method for determining the actual refrigerant charge in HVAC systems are described. The meter includes means for determining an optimum refrigerant charge from system subcooling and system component parameters. The meter also includes means for determining the ratio of the actual refrigerant charge to the optimum refrigerant charge. Finally, the meter includes means for determining the actual refrigerant charge from the optimum refrigerant charge and the ratio of the actual refrigerant charge to the optimum refrigerant charge.

Energy Digest.

ERIC Educational Resources Information Center

Gaddy, Carol T., Ed.; Wells, Kathy, Ed.

This collection of reprints offers practical solutions, not readily available elsewhere, to everyday energy problems, such as high utility bills, insulating windows, getting more gas mileage, or buying a more efficient washer or refrigerator. The Arkansas Energy Office provides a weekly column of energy news and conservation tips to newspapers,…

Micro-structured heat exchanger for cryogenic mixed refrigerant cycles

NASA Astrophysics Data System (ADS)

Gomse, D.; Reiner, A.; Rabsch, G.; Gietzelt, T.; Brandner, J. J.; Grohmann, S.

2017-12-01

Mixed refrigerant cycles (MRCs) offer a cost- and energy-efficient cooling method for the temperature range between 80 and 200 K. The performance of MRCs is strongly influenced by entropy production in the main heat exchanger. High efficiencies thus require small temperature gradients among the fluid streams, as well as limited pressure drop and axial conduction. As temperature gradients scale with heat flux, large heat transfer areas are necessary. This is best achieved with micro-structured heat exchangers, where high volumetric heat transfer areas can be realized. The reliable design of MRC heat exchangers is challenging, since two-phase heat transfer and pressure drop in both fluid streams have to be considered simultaneously. Furthermore, only few data on the convective boiling and condensation kinetics of zeotropic mixtures is available in literature. This paper presents a micro-structured heat exchanger designed with a newly developed numerical model, followed by experimental results on the single-phase pressure drop and their implications on the hydraulic diameter.

Synthetic zeolites and other microporous oxide molecular sieves

PubMed Central

Sherman, John D.

1999-01-01

Use of synthetic zeolites and other microporous oxides since 1950 has improved insulated windows, automobile air-conditioning, refrigerators, air brakes on trucks, laundry detergents, etc. Their large internal pore volumes, molecular-size pores, regularity of crystal structures, and the diverse framework chemical compositions allow “tailoring” of structure and properties. Thus, highly active and selective catalysts as well as adsorbents and ion exchangers with high capacities and selectivities were developed. In the petroleum refining and petrochemical industries, zeolites have made possible cheaper and lead-free gasoline, higher performance and lower-cost synthetic fibers and plastics, and many improvements in process efficiency and quality and in performance. Zeolites also help protect the environment by improving energy efficiency, reducing automobile exhaust and other emissions, cleaning up hazardous wastes (including the Three Mile Island nuclear power plant and other radioactive wastes), and, as specially tailored desiccants, facilitating the substitution of new refrigerants for the ozone-depleting chlorofluorocarbons banned by the Montreal Protocol. PMID:10097059

Logic gates realized by nonvolatile GeTe/Sb2Te3 super lattice phase-change memory with a magnetic field input

NASA Astrophysics Data System (ADS)

Lu, Bin; Cheng, Xiaomin; Feng, Jinlong; Guan, Xiawei; Miao, Xiangshui

2016-07-01

Nonvolatile memory devices or circuits that can implement both storage and calculation are a crucial requirement for the efficiency improvement of modern computer. In this work, we realize logic functions by using [GeTe/Sb2Te3]n super lattice phase change memory (PCM) cell in which higher threshold voltage is needed for phase change with a magnetic field applied. First, the [GeTe/Sb2Te3]n super lattice cells were fabricated and the R-V curve was measured. Then we designed the logic circuits with the super lattice PCM cell verified by HSPICE simulation and experiments. Seven basic logic functions are first demonstrated in this letter; then several multi-input logic gates are presented. The proposed logic devices offer the advantages of simple structures and low power consumption, indicating that the super lattice PCM has the potential in the future nonvolatile central processing unit design, facilitating the development of massive parallel computing architecture.

[Response of yield, quality and nitrogen use efficiency to nitrogen fertilizer from mechanical transplanting super japonica rice].

PubMed

Wei, Hai-Yan; Wang, Ya-Jiang; Meng, Tian-Yao; Ge, Meng-Jie; Zhang, Hong-Cheng; Dai, Qi-Gen; Huo, Zhong-Yang; Xu, Ke

2014-02-01

Five super japonica rice cultivars were grown by mechanical transplanting in field and seven N treatments with total N application rate of 0, 150, 187.5, 225, 262.5, 300 and 337.5 kg x hm(-2) respectively were adopted to study the effects of N rate on rice yield, quality and N use efficiency. The differences between N requirement for obtaining the highest yield and for achieving the best economic benefit were compared. With the increase of N fertilizer rate, the yields of five super japonica rice cultivars increased firstly and then descended, achieving the highest yield at the N level of 300 kg x hm(-2) ranging from 10.33-10.60 kg x hm(-2). Yield increase mainly attributed to the large number of spikelet, for the total spikelet number of each rice cultivar reached the maximum value at the 300 kg x hm(-2) N level. With the increase of N application, the rates of brown rice, milled rice, head milled rice and the protein content of the five super japonica rice cultivars were all increased, and the rates of brown rice, milled rice, head milled rice and the protein con- tent were higher at 337.5 kg x hm(-2) N level than at 0 kg x hm(-2) N level by 3.3%-4.2%, 2.9%-6.0%, 4.4%-33.7% and 23.8%-44.3%, respectively. While the amylose content, gel consistency and taste value of the five rice cultivars were all decreased, and the amylose content, gel consistency and taste value were lower at 337.5 kg x hm(-2) N level than at 0 kg x hm(-2) N level by 12.4%-38.9%, 10.3%-28.5% and 20.3%-29.7%, respectively. The chalkiness increased firstly and then decreased while the change of chalky rate varied with the cultivars. With the increase of N application, the N use efficiency, agronomic N use efficiency and physiological N use efficiency decreased while the N uptake of grain increased significantly. If the cost of N fertilizer was taken into account, the N fertilizer amount to obtain the optimal economic benefits would be 275.68 kg x hm(-2) with the corresponding yield of 9.97 t x hm(-2). Therefore, in the existing super rice production, classified management of N fertilizer would be required to meet differentiated demands of high yield, good quality, high efficiency, low N fertilizer input and so on.

Analysis of ingredient functionality and formulation optimization of an instant peanut beverage mix.

PubMed

Howard, Brandy M; Hung, Yen-Con; McWatters, S Kay

2010-01-01

Powder for an instant shake-style beverage was created using partially defatted peanut flour (12% fat), granulated sugar, and nonfat dry milk (NFDM). The 3 main components, along with constant amounts of stabilizing gums and anti-caking silica, were mixed together and finely milled in a Super Wing Mill to further reduce the particle sizes. Drinks from each formula variation were prepared and analyzed for viscosity (digital viscometer), color (colorimeter), and separation rate. Each beverage was also analyzed by consumers to determine acceptability of flavor, mouth-feel, and color. Physical test results show that viscosity increased with increasing proportion of peanut flour in the formula, and viscosity decreased with increasing levels of sugar and NFDM. For each formula, the samples at refrigerated temperature (4 degrees C) were less viscous than those at ambient temperatures (23 to 25 degrees C). Color values show that the beverage powder color was mostly influenced by peanut flour percentage, becoming darker with increasing levels of peanut flour. Prepared beverage color was influenced by both NFDM and peanut flour percentage; lightness increased with increasing NFDM percentage and decreased with increasing peanut flour percentage. Separation rates were most affected by the proportion of NFDM in the formula; higher levels decreased the rate of separation. Refrigeration slowed the rate of separation in all samples. Response surface analysis of consumer test data showed that the most acceptable formulation for the peanut beverage included approximately equal amounts of peanut flour, sugar, and NFDM.

Interesting electrochemical properties of novel three-dimensional Ag3PO4 tetrapods as a new super capacitor electrode material

NASA Astrophysics Data System (ADS)

Li, Shouguang; Teng, Fei; Chen, Mindong; Li, Na; Hua, Xia; Wang, Kai; Li, Min

2014-05-01

The novel three-dimensional (3D) silver phosphate tetrapods (TA) are synthesized and employed as a super capacitor electrode material. The electrochemical properties are investigated by cyclic voltammetry (CV), chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS). It is interesting that compared with irregular silver phosphate particles (IA), TA shows a higher capacitance (250 vs. 160 F g-1), and a higher coulombic efficiency (80% vs. 74%), which is mainly ascribed to the 3D microstructure and its high conductivity. To the best of our knowledge, this is the first report on silver phosphate as a super capacitor material.

Transfer Efficiency and Cooling Cost by Thermal Loss based on Nitrogen Evaporation Method for Superconducting MAGLEV System

NASA Astrophysics Data System (ADS)

Chung, Y. D.; Kim, D. W.; Lee, C. Y.

2017-07-01

This paper presents the feasibility of technical fusion between wireless power transfer (WPT) and superconducting technology to improve the transfer efficiency and evaluate operating costs such as refrigerant consumption. Generally, in WPT technology, the various copper wires have been adopted. From this reason, the transfer efficiency is limited since the copper wires of Q value are intrinsically critical point. On the other hand, as superconducting wires keep larger current density and relatively higher Q value, the superconducting resonance coil can be expected as a reasonable option to deliver large transfer power as well as improve the transfer ratio since it exchanges energy at a much higher rate and keeps stronger magnetic fields out. However, since superconducting wires should be cooled indispensably, the cooling cost of consumed refrigerant for resonance HTS wires should be estimated. In this study, the transmission ratios using HTS resonance receiver (Rx) coil and various cooled and noncooled copper resonance Rx coils were presented under non cooled copper antenna within input power of 200 W of 370 kHz respectively. In addition, authors evaluated cooling cost of liquid nitrogen for HTS resonance coil and various cooled copper resonance coils based on nitrogen evaporation method.

Ytterbium-doped glass-ceramics for optical refrigeration.

PubMed

Filho, Elton Soares de Lima; Krishnaiah, Kummara Venkata; Ledemi, Yannick; Yu, Ye-Jin; Messaddeq, Younes; Nemova, Galina; Kashyap, Raman

2015-02-23

We report for the first time the characterization of glass-ceramics for optical refrigeration. Ytterbium-doped nanocrystallites were grown in an oxyfluoride glass matrix of composition 2YbF(3):30SiO(2)-15Al(2)O(3)-25CdF(2)-22PbF(2)-4YF(3), forming bulk glass-ceramics at three different crystalisation levels. The samples are compared with a corresponding uncrystalised (glass) sample, as well as a Yb:YAG sample which has presented optical cooling. The measured X-ray diffraction spectra, and thermal capacities of the samples are reported. We also report for the first time the use of Yb:YAG as a reference for absolute photometric quantum efficiency measurement, and use the same setup to characterize the glass and glass-ceramic samples. The cooling figure-of-merit was measured by optical calorimetry using a fiber Bragg grating and found to depend on the level of crystallization of the sample, and that samples with nanocrystallites result in higher quantum efficiency and lower background absorption than the pure-glass sample. In addition to laser-induced cooling, the glass-ceramics have the potential to serve as a reference for quantum efficiency measurements.

Flow field analysis of high-speed helium turboexpander for cryogenic refrigeration and liquefaction cycles

NASA Astrophysics Data System (ADS)

Sam, Ashish Alex; Ghosh, Parthasarathi

2017-03-01

Turboexpander constitutes one of the vital components of Claude cycle based helium refrigerators and liquefiers that are gaining increasing technological importance. These turboexpanders which are of radial inflow in configuration are generally high-speed micro turbines, due to the low molecular weight and density of helium. Any improvement in efficiency of these machines requires a detailed understanding of the flow field. Computational Fluid Dynamics analysis (CFD) has emerged as a necessary tool for the determination of the flow fields in cryogenic turboexpanders, which is often not possible through experiments. In the present work three-dimensional transient flow analysis of a cryogenic turboexpander for helium refrigeration and liquefaction cycles were performed using Ansys CFX®, to understand the flow field of a high-speed helium turboexpander, which in turn will help in taking appropriate decisions regarding modifications of established design methodology for improved efficiency of these machines. The turboexpander is designed based on Balje's nsds diagram and the inverse design blade profile generation formalism prescribed by Hasselgruber and Balje. The analyses include the study of several losses, their origins, the increase in entropy due to these losses, quantification of losses and the effects of various geometrical parameters on these losses. Through the flow field analysis it was observed that in the nozzle, flow separation at the nozzle blade suction side and trailing edge vortices resulted in loss generation, which calls for better nozzle blade profile. The turbine wheel flow field analysis revealed that the significant geometrical parameters of the turbine wheel blade like blade inlet angle, blade profile, tip clearance height and trailing edge thickness need to be optimised for improved performance of the turboexpander. The detailed flow field analysis in this paper can be used to improve the mean line design methodology for turboexpanders used in helium refrigeration and liquefaction cycles.

Feasibility of an appliance energy testing and labeling program for Sri Lanka

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biermayer, Peter; Busch, John; Hakim, Sajid

2000-04-01

A feasibility study evaluated the costs and benefits of establishing a program for testing, labeling and setting minimum efficiency standards for appliances and lighting in Sri Lanka. The feasibility study included: refrigerators, air-conditioners, flourescent lighting (ballasts & CFls), ceiling fans, motors, and televisions.

Super electron donor-mediated reductive transformation of nitrobenzenes: a novel strategy to synthesize azobenzenes and phenazines.

PubMed

Nozawa-Kumada, Kanako; Abe, Erina; Ito, Shungo; Shigeno, Masanori; Kondo, Yoshinori

2018-05-02

The transformation of nitrobenzenes into azobenzenes by pyridine-derived super electron donor 2 is described. This method provides an efficient synthesis of azobenzenes because of not requiring the use of expensive transition-metals, toxic or flammable reagents, or harsh conditions. Moreover, when using 2-fluoronitrobenzenes as substrates, phenazines were found to be obtained. The process affords a novel synthesis of phenazines.

An Example-Based Super-Resolution Algorithm for Selfie Images

PubMed Central

William, Jino Hans; Venkateswaran, N.; Narayanan, Srinath; Ramachandran, Sandeep

2016-01-01

A selfie is typically a self-portrait captured using the front camera of a smartphone. Most state-of-the-art smartphones are equipped with a high-resolution (HR) rear camera and a low-resolution (LR) front camera. As selfies are captured by front camera with limited pixel resolution, the fine details in it are explicitly missed. This paper aims to improve the resolution of selfies by exploiting the fine details in HR images captured by rear camera using an example-based super-resolution (SR) algorithm. HR images captured by rear camera carry significant fine details and are used as an exemplar to train an optimal matrix-value regression (MVR) operator. The MVR operator serves as an image-pair priori which learns the correspondence between the LR-HR patch-pairs and is effectively used to super-resolve LR selfie images. The proposed MVR algorithm avoids vectorization of image patch-pairs and preserves image-level information during both learning and recovering process. The proposed algorithm is evaluated for its efficiency and effectiveness both qualitatively and quantitatively with other state-of-the-art SR algorithms. The results validate that the proposed algorithm is efficient as it requires less than 3 seconds to super-resolve LR selfie and is effective as it preserves sharp details without introducing any counterfeit fine details. PMID:27064500

High Efficiency Variable Speed Versatile Power Air Conditioning System

DTIC Science & Technology

2013-08-08

Design concept applicable for wide range of HVAC and refrigeration systems • One TXV size can be used for a wide range of cooling capacity...versatility, can run from AC and DC sources Cooling load adaptive, variable Speed Fully operable up to 140 degrees Fahrenheit 15. SUBJECT TERMS 16. SECURITY...ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 High Efficiency HVAC &R Technology

Giant electrocaloric and energy storage performance of [(K0.5Na0.5)NbO3](1-x)-[LiSbO3] x nanocrystalline ceramics.

PubMed

Kumar, Raju; Singh, Satyendra

2018-02-16

Electrocaloric (EC) refrigeration, an EC effect based technology has been accepted as an auspicious way in the development of next generation refrigeration due to high efficiency and compact size. Here, we report the results of our experimental investigations on electrocaloric response and electrical energy storage properties in lead-free nanocrystalline (1 - x)K 0.5 Na 0.5 NbO 3 -xLiSbO 3 (KNN-xLS) ceramics in the range of 0.015 ≤ x ≤ 0.06 by the indirect EC measurements. Doping of LiSbO 3 has lowered both the transitions (T C and T O-T ) of KNN to the room temperature side effectively. A maximal value of EC temperature change, ΔT = 3.33 K was obtained for the composition with x = 0.03 at 345 K under an external electric field of 40 kV/cm. The higher value of EC responsivity, ζ = 8.32 × 10 -7  K.m/V is found with COP of 8.14 and recoverable energy storage of 0.128 J/cm 3 with 46% efficiency for the composition of x = 0.03. Our investigations show that this material is a very promising candidate for electrocaloric refrigeration and energy storage near room temperature.

The Operating Principle of a Fully Solid State Active Magnetic Regenerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelaziz, Omar

As an alternative refrigeration technology, magnetocaloric refrigeration has the potential to be safer, quieter, more efficient, and more environmentally friendly than the conventional vapor compression refrigeration technology. Most of the reported active magnetic regenerator (AMR) systems that operate based on the magnetocaloric effect use heat transfer fluid to exchange heat, which results in complicated mechanical subsystems and components such as rotating valves and hydraulic pumps. This paper presents an operating principle of a fully solid state AMR, in which an alternative mechanism for heat transfer between the AMR and the heat source/sink is proposed. The operating principle of the fullymore » solid state AMR is based on moving rods/sheets (e.g. copper, brass, iron or aluminum), which are employed to replace the heat transfer fluid. Such fully solid state AMR would provide a significantly higher heat transfer rate than a conventional AMR because the conductivity of moving solid rods/plates is high and it enables the increase in the machine operating frequency hence the cooling capacity. The details of operating principle are presented and discussed here. One of the key enabling features for this technology is the contact between the moving rods/sheets and magnetocaloric material, and heat exchange mechanism at the heat source/sink. This paper provides an overview of the design for a fully solid state magnetocaloric refrigeration system along with guidelines for their optimal design.« less

Performance Testing of Jefferson Lab 12 GeV Helium Screw Compressors

DOE PAGES

Knudsen, P.; Ganni, V.; Dixon, K.; ...

2015-08-10

Oil injected screw compressors have essentially superseded all other types of compressors in modern helium refrigeration systems due to their large displacement capacity, reliability, minimal vibration, and capability of handling helium's high heat of compression. At the present state of compressor system designs for helium refrigeration systems, typically two-thirds of the lost input power is due to the compression system. It is important to understand the isothermal and volumetric efficiencies of these machines to help properly design the compression system to match the refrigeration process. It is also important to identify those primary compressor skid exergetic loss mechanisms which maymore » be reduced, thereby offering the possibility of significantly reducing the input power to helium refrigeration processes which are extremely energy intensive. This paper summarizes the results collected during the commissioning of the new compressor system for Jefferson Lab's (JLab's) 12 GeV upgrade. The compressor skid packages were designed by JLab and built to print by industry. They incorporate a number of modifications not typical of helium screw compressor packages and most importantly allow a very wide range of operation so that JLab's patented Floating Pressure Process can be fully utilized. This paper also summarizes key features of the skid design that allow this process and facilitate the maintenance and reliability of these helium compressor systems.« less

Performance Testing of Jefferson Lab 12 GeV Helium Screw Compressors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knudsen, P.; Ganni, V.; Dixon, K.

Oil injected screw compressors have essentially superseded all other types of compressors in modern helium refrigeration systems due to their large displacement capacity, reliability, minimal vibration, and capability of handling helium's high heat of compression. At the present state of compressor system designs for helium refrigeration systems, typically two-thirds of the lost input power is due to the compression system. It is important to understand the isothermal and volumetric efficiencies of these machines to help properly design the compression system to match the refrigeration process. It is also important to identify those primary compressor skid exergetic loss mechanisms which maymore » be reduced, thereby offering the possibility of significantly reducing the input power to helium refrigeration processes which are extremely energy intensive. This paper summarizes the results collected during the commissioning of the new compressor system for Jefferson Lab's (JLab's) 12 GeV upgrade. The compressor skid packages were designed by JLab and built to print by industry. They incorporate a number of modifications not typical of helium screw compressor packages and most importantly allow a very wide range of operation so that JLab's patented Floating Pressure Process can be fully utilized. This paper also summarizes key features of the skid design that allow this process and facilitate the maintenance and reliability of these helium compressor systems.« less

Integrated Refrigeration and Storage for Advanced Liquid Hydrogen Operations

NASA Technical Reports Server (NTRS)

Swanger, A. M.; Notardonato, W. U.; Johnson, W. L.; Tomsik, T. M.

2016-01-01

NASA has used liquefied hydrogen (LH2) on a large scale since the beginning of the space program as fuel for the Centaur and Apollo upper stages, and more recently to feed the three space shuttle main engines. The LH2 systems currently in place at the Kennedy Space Center (KSC) launch pads are aging and inefficient compared to the state-of-the-art. Therefore, the need exists to explore advanced technologies and operations that can drive commodity costs down, and provide increased capabilities. The Ground Operations Demonstration Unit for Liquid Hydrogen (GODU-LH2) was developed at KSC to pursue these goals by demonstrating active thermal control of the propellant state by direct removal of heat using a cryocooler. The project has multiple objectives including zero loss storage and transfer, liquefaction of gaseous hydrogen, and densification of liquid hydrogen. The key technology challenge was efficiently integrating the cryogenic refrigerator into the LH2 storage tank. A Linde LR1620 Brayton cycle refrigerator is used to produce up to 900W cooling at 20K, circulating approximately 22 g/s gaseous helium through the hydrogen via approximately 300 m of heat exchanger tubing. The GODU-LH2 system is fully operational, and is currently under test. This paper will discuss the design features of the refrigerator and storage system, as well as the current test results.

Molecular analysis of bacterial communities in raw cow milk and the impact of refrigeration on its structure and dynamics.

PubMed

Raats, Dina; Offek, Maya; Minz, Dror; Halpern, Malka

2011-05-01

The impact of refrigeration on raw cow milk bacterial communities in three farm bulk tanks and three dairy plant silo tanks was studied using two methods: DGGE and cloning. Both methods demonstrated that bacterial taxonomic diversity decreased during refrigeration. Gammaproteobacteria, especially Pseudomonadales, dominated the milk after refrigeration. Farm samples and dairy plant samples differed in their microbial community composition, the former showing prevalence of Gram-positive bacteria affiliated with the classes Bacilli, Clostridia and Actinobacteria, the latter showing prevalence of Gram-negative species belonging to the Gammaproteobacteria class. Actinobacteria prevalence in the farm milk samples immediately after collection stood at about 25% of the clones. A previous study had found that psychrotolerant Actinobacteria identified in raw cow milk demonstrated both lipolytic and proteolytic enzymatic activity. Thus, we conclude that although Pseudomonadales play an important role in milk spoilage after long periods of cold incubation, Actinobacteria occurrence may play an important role when assessing the quality of milk arriving at the dairy plant from different farms. As new cooling technologies reduce the initial bacterial counts of milk to very low levels, more sensitive and efficient methods to evaluate the bacterial quality of raw milk are required. The present findings are an important step towards achieving this goal. Copyright © 2010 Elsevier Ltd. All rights reserved.

Relationship between composition of mixture charged and that in circulation in an auto refrigerant cascade and a J-T refrigerator operating in liquid refrigerant supply mode

NASA Astrophysics Data System (ADS)

Sreenivas, Bura; Nayak, H. Gurudath; Venkatarathnam, G.

2017-01-01

The composition of the refrigerant mixture in circulation during steady state operation of J-T and allied refrigerators is not the same as that charged due to liquid hold up in the heat exchangers and phase separators, as well as the differential solubility of different refrigerant components in the compressor lubricating oil. The performance of refrigerators/liquefiers operating on mixed refrigerant cycles is dependent on the mixture composition. It is therefore important to charge the right mixture that results in an optimum composition in circulation during steady state operation. The relationship between the charged and circulating composition has been experimentally studied in a J-T refrigerator operating in the liquid refrigerant supply (LRS) mode and an auto refrigerant cascade refrigerator (with a phase separator) operating in the gas refrigerant supply (GRS) mode. The results of the study are presented in this work. The results show that the method presented earlier for J-T refrigerators operating in GRS mode is also applicable in the case of refrigerators studied in this work.

Chemically assisted mechanical refrigeration process

DOEpatents

Vobach, Arnold R.

1987-01-01

There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer (11) at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer (11) to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator (10) to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator.

Chemically assisted mechanical refrigeration process

DOEpatents

Vobach, Arnold R.

1987-01-01

There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer (11) at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer (11) to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator (10) to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing he evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator.

Chemically assisted mechanical refrigeration process

DOEpatents

Vobach, A.R.

1987-06-23

There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator. 5 figs.

Chemically assisted mechanical refrigeration process

DOEpatents

Vobach, A.R.

1987-11-24

There is provided a chemically assisted mechanical refrigeration process including the steps of: mechanically compressing a refrigerant stream which includes vaporized refrigerant; contacting the refrigerant with a solvent in a mixer at a pressure sufficient to promote substantial dissolving of the refrigerant in the solvent in the mixer to form a refrigerant-solvent solution while concurrently placing the solution in heat exchange relation with a working medium to transfer energy to the working medium, said refrigerant-solvent solution exhibiting a negative deviation from Raoult's Law; reducing the pressure over the refrigerant-solvent solution in an evaporator to allow the refrigerant to vaporize and substantially separate from the solvent while concurrently placing the evolving refrigerant-solvent solution in heat exchange relation with a working medium to remove energy from the working medium to thereby form a refrigerant stream and a solvent stream; and passing the solvent and refrigerant stream from the evaporator. 5 figs.

Refrigerant charge management in a heat pump water heater

DOEpatents

Chen, Jie; Hampton, Justin W.

2016-07-05

Heat pumps that heat or cool a space and that also heat water, refrigerant management systems for such heat pumps, and methods of managing refrigerant charge. Various embodiments remove idle refrigerant from a heat exchanger that is not needed for transferring heat by opening a refrigerant recovery valve and delivering the idle refrigerant from the heat exchanger to an inlet port on the compressor. The heat exchanger can be isolated by closing an electronic expansion valve, actuating a refrigerant management valve, or both. Refrigerant charge can be controlled by controlling how much refrigerant is drawn from the heat exchanger, by letting some refrigerant back into the heat exchanger, or both. Heat pumps can be operated in different modes of operation, and various components can be interconnected with refrigerant conduit. Some embodiments deliver refrigerant gas to the heat exchanger and drive liquid refrigerant out prior to isolating the heat exchanger.

Floating Loop System For Cooling Integrated Motors And Inverters Using Hot Liquid Refrigerant

DOEpatents

Hsu, John S [Oak Ridge, TN; Ayers, Curtis W [Kingston, TN; Coomer, Chester [Knoxville, TN; Marlino, Laura D [Oak Ridge, TN

2006-02-07

A floating loop vehicle component cooling and air-conditioning system having at least one compressor for compressing cool vapor refrigerant into hot vapor refrigerant; at least one condenser for condensing the hot vapor refrigerant into hot liquid refrigerant by exchanging heat with outdoor air; at least one floating loop component cooling device for evaporating the hot liquid refrigerant into hot vapor refrigerant; at least one expansion device for expanding the hot liquid refrigerant into cool liquid refrigerant; at least one air conditioning evaporator for evaporating the cool liquid refrigerant into cool vapor refrigerant by exchanging heat with indoor air; and piping for interconnecting components of the cooling and air conditioning system.

Improvements in the efficiency of turboexpanders in cryogenic applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agahi, R.R.; Lin, M.C.; Ershaghi, B.

1996-12-31

Process designers have utilized turboexpanders in cryogenic processes because of their higher thermal efficiencies when compared with conventional refrigeration cycles. Process design and equipment performance have improved substantially through the utilization of modern technologies. Turboexpander manufacturers have also adopted Computational Fluid Dynamic Software, Computer Numerical Control Technology and Holography Techniques to further improve an already impressive turboexpander efficiency performance. In this paper, the authors explain the design process of the turboexpander utilizing modern technology. Two cases of turboexpanders processing helium (4.35{degrees}K) and hydrogen (56{degrees}K) will be presented.

Single-shot and single-sensor high/super-resolution microwave imaging based on metasurface.

PubMed

Wang, Libo; Li, Lianlin; Li, Yunbo; Zhang, Hao Chi; Cui, Tie Jun

2016-06-01

Real-time high-resolution (including super-resolution) imaging with low-cost hardware is a long sought-after goal in various imaging applications. Here, we propose broadband single-shot and single-sensor high-/super-resolution imaging by using a spatio-temporal dispersive metasurface and an imaging reconstruction algorithm. The metasurface with spatio-temporal dispersive property ensures the feasibility of the single-shot and single-sensor imager for super- and high-resolution imaging, since it can convert efficiently the detailed spatial information of the probed object into one-dimensional time- or frequency-dependent signal acquired by a single sensor fixed in the far-field region. The imaging quality can be improved by applying a feature-enhanced reconstruction algorithm in post-processing, and the desired imaging resolution is related to the distance between the object and metasurface. When the object is placed in the vicinity of the metasurface, the super-resolution imaging can be realized. The proposed imaging methodology provides a unique means to perform real-time data acquisition, high-/super-resolution images without employing expensive hardware (e.g. mechanical scanner, antenna array, etc.). We expect that this methodology could make potential breakthroughs in the areas of microwave, terahertz, optical, and even ultrasound imaging.

Performance of solar refrigerant ejector refrigerating machine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Khalidy, N.A.H.

1997-12-31

In this work a detailed analysis for the ideal, theoretical, and experimental performance of a solar refrigerant ejector refrigerating machine is presented. A comparison of five refrigerants to select a desirable one for the system is made. The theoretical analysis showed that refrigerant R-113 is more suitable for use in the system. The influence of the boiler, condenser, and evaporator temperatures on system performance is investigated experimentally in a refrigerant ejector refrigerating machine using R-113 as a working refrigerant.

Experimental investigation of the ecological hybrid refrigeration cycle

NASA Astrophysics Data System (ADS)

Cyklis, Piotr; Kantor, Ryszard; Ryncarz, Tomasz; Górski, Bogusław; Duda, Roman

2014-09-01

The requirements for environmentally friendly refrigerants promote application of CO2 and water as working fluids. However there are two problems related to that, namely high temperature limit for CO2 in condenser due to the low critical temperature, and low temperature limit for water being the result of high triple point temperature. This can be avoided by application of the hybrid adsorption-compression system, where water is the working fluid in the adsorption high temperature cycle used to cool down the CO2 compression cycle condenser. The adsorption process is powered with a low temperature renewable heat source as solar collectors or other waste heat source. The refrigeration system integrating adsorption and compression system has been designed and constructed in the Laboratory of Thermodynamics and Thermal Machine Measurements of Cracow University of Technology. The heat source for adsorption system consists of 16 tube tulbular collectors. The CO2 compression low temperature cycle is based on two parallel compressors with frequency inverter. Energy efficiency and TEWI of this hybrid system is quite promising in comparison with the compression only systems.

Helium dilution refrigeration system

DOEpatents

Roach, Patrick R.; Gray, Kenneth E.

1988-01-01

A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains .sup.3 He and .sup.4 He liquids which are precooled by a coupled container containing .sup.3 He liquid, enabling the phase separation of a .sup.3 He rich liquid phase from a dilute .sup.3 He-.sup.4 He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the .sup.3 He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute .sup.3 He-.sup.4 He liquid phase.

Helium dilution refrigeration system

DOEpatents

Roach, P.R.; Gray, K.E.

1988-09-13

A helium dilution refrigeration system operable over a limited time period, and recyclable for a next period of operation is disclosed. The refrigeration system is compact with a self-contained pumping system and heaters for operation of the system. A mixing chamber contains [sup 3]He and [sup 4]He liquids which are precooled by a coupled container containing [sup 3]He liquid, enabling the phase separation of a [sup 3]He rich liquid phase from a dilute [sup 3]He-[sup 4]He liquid phase which leads to the final stage of a dilution cooling process for obtaining low temperatures. The mixing chamber and a still are coupled by a fluid line and are maintained at substantially the same level with the still cross sectional area being smaller than that of the mixing chamber. This configuration provides maximum cooling power and efficiency by the cooling period ending when the [sup 3]He liquid is depleted from the mixing chamber with the mixing chamber nearly empty of liquid helium, thus avoiding unnecessary and inefficient cooling of a large amount of the dilute [sup 3]He-[sup 4]He liquid phase. 2 figs.

Thermofluid Analysis of Magnetocaloric Refrigeration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelaziz, Omar; Gluesenkamp, Kyle R; Vineyard, Edward Allan

While there have been extensive studies on thermofluid characteristics of different magnetocaloric refrigeration systems, a conclusive optimization study using non-dimensional parameters which can be applied to a generic system has not been reported yet. In this study, a numerical model has been developed for optimization of active magnetic refrigerator (AMR). This model is computationally efficient and robust, making it appropriate for running the thousands of simulations required for parametric study and optimization. The governing equations have been non-dimensionalized and numerically solved using finite difference method. A parametric study on a wide range of non-dimensional numbers has been performed. While themore » goal of AMR systems is to improve the performance of competitive parameters including COP, cooling capacity and temperature span, new parameters called AMR performance index-1 have been introduced in order to perform multi objective optimization and simultaneously exploit all these parameters. The multi-objective optimization is carried out for a wide range of the non-dimensional parameters. The results of this study will provide general guidelines for designing high performance AMR systems.« less

LARGE SCALE REFRIGERATION PLANT FOR GROUND TESTING THE JAMES WEBB TELESCOPE AT NASA JOHNSON SPACE CENTER

DOE Office of Scientific and Technical Information (OSTI.GOV)

P. Arnold, Lutz Decker, D. Howe, J. Urbin, Jonathan Homan, Carl Reis, J. Creel, V. Ganni, P. Knudsen, A. Sidi-Yekhlef

The James Webb Telescope is the successor to the Hubble Telescope and will be placed in an orbit of 1.5 million km from earth. Before launch in 2014, the telescope will be tested in NASA Johnson Space Center's (JSC) space simulation chamber, Chamber A. The tests will be conducted at deep space conditions. Chamber A's helium cryo-panels are currently cooled down to 20 K by two Linde 3.5 kW helium refrigerators. The new 12.5 kW, 20-K helium coldbox described in this paper is part of the upgrade to the chamber systems for this large test program. The Linde coldbox willmore » provide refrigeration in several operating modes where the temperature of the chamber is being controlled with a high accuracy due to the demanding NASA test requirements. The implementation of two parallel expansion turbine strings and the Ganni cycle—Floating Pressure process results in a highly efficient and flexible process that minimizes the electrical input power. This paper will describe the collaboration and execution of the coldbox project.« less

Optimal design of solid oxide fuel cell, ammonia-water single effect absorption cycle and Rankine steam cycle hybrid system

NASA Astrophysics Data System (ADS)

Mehrpooya, Mehdi; Dehghani, Hossein; Ali Moosavian, S. M.

2016-02-01

A combined system containing solid oxide fuel cell-gas turbine power plant, Rankine steam cycle and ammonia-water absorption refrigeration system is introduced and analyzed. In this process, power, heat and cooling are produced. Energy and exergy analyses along with the economic factors are used to distinguish optimum operating point of the system. The developed electrochemical model of the fuel cell is validated with experimental results. Thermodynamic package and main parameters of the absorption refrigeration system are validated. The power output of the system is 500 kW. An optimization problem is defined in order to finding the optimal operating point. Decision variables are current density, temperature of the exhaust gases from the boiler, steam turbine pressure (high and medium), generator temperature and consumed cooling water. Results indicate that electrical efficiency of the combined system is 62.4% (LHV). Produced refrigeration (at -10 °C) and heat recovery are 101 kW and 22.1 kW respectively. Investment cost for the combined system (without absorption cycle) is about 2917 kW-1.

Preliminary Analysis of a Fully Solid State Magnetocaloric Refrigeration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdelaziz, Omar

Magnetocaloric refrigeration is an alternative refrigeration technology with significant potential energy savings compared to conventional vapor compression refrigeration technology. Most of the reported active magnetic regenerator (AMR) systems that operate based on the magnetocaloric effect use heat transfer fluid to exchange heat, which results in complicated mechanical subsystems and components such as rotating valves and hydraulic pumps. In this paper, we propose an alternative mechanism for heat transfer between the AMR and the heat source/sink. High-conductivity moving rods/sheets (e.g. copper, brass, iron, graphite, aluminum or composite structures from these) are utilized instead of heat transfer fluid significantly enhancing the heatmore » transfer rate hence cooling/heating capacity. A one-dimensional model is developed to study the solid state AMR. In this model, the heat exchange between the solid-solid interfaces is modeled via a contact conductance, which depends on the interface apparent pressure, material hardness, thermal conductivity, surface roughness, surface slope between the interfaces, and material filled in the gap between the interfaces. Due to the tremendous impact of the heat exchange on the AMR cycle performance, a sensitivity analysis is conducted employing a response surface method, in which the apparent pressure, effective surface roughness and grease thermal conductivity are the uncertainty factors. COP and refrigeration capacity are presented as the response in the sensitivity analysis to reveal the important factors influencing the fully solid state AMR and optimize the solid state AMR efficiency. The performances of fully solid state AMR and traditional AMR are also compared and discussed in present work. The results of this study will provide general guidelines for designing high performance solid state AMR systems.« less

78 FR 57139 - Decision and Order Granting a Waiver to Panasonic Appliances Refrigeration Systems Corporation of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-17

... procedures that are reasonably designed to produce results that measure energy efficiency, energy use, or... more design characteristics that prevent testing according to the prescribed test procedure, or (2... true energy consumption characteristics as to provide materially inaccurate comparative data. 10 CFR...

Ecological efficiency in China and its influencing factors-a super-efficient SBM metafrontier-Malmquist-Tobit model study.

PubMed

Ma, Xiaojun; Wang, Changxin; Yu, Yuanbo; Li, Yudong; Dong, Biying; Zhang, Xinyu; Niu, Xueqi; Yang, Qian; Chen, Ruimin; Li, Yifan; Gu, Yihan

2018-05-15

Ecological problem is one of the core issues that restrain China's economic development at present, and it is urgently needed to be solved properly and effectively. Based on panel data from 30 regions, this paper uses a super efficiency slack-based measure (SBM) model that introduces the undesirable output to calculate the ecological efficiency, and then uses traditional and metafrontier-Malmquist index method to study regional change trends and technology gap ratios (TGRs). Finally, the Tobit regression and principal component analysis methods are used to analysis the main factors affecting eco-efficiency and impact degree. The results show that about 60% of China's provinces have effective eco-efficiency, and the overall ecological efficiency of China is at the superior middling level, but there is a serious imbalance among different provinces and regions. Ecological efficiency has an obvious spatial cluster effect. There are differences among regional TGR values. Most regions show a downward trend and the phenomenon of focusing on economic development at the expense of ecological protection still exists. Expansion of opening to the outside, increases in R&D spending, and improvement of population urbanization rate have positive effects on eco-efficiency. Blind economic expansion, increases of industrial structure, and proportion of energy consumption have negative effects on eco-efficiency.

From quantum heat engines to laser cooling: Floquet theory beyond the Born–Markov approximation

NASA Astrophysics Data System (ADS)

Restrepo, Sebastian; Cerrillo, Javier; Strasberg, Philipp; Schaller, Gernot

2018-05-01

We combine the formalisms of Floquet theory and full counting statistics with a Markovian embedding strategy to access the dynamics and thermodynamics of a periodically driven thermal machine beyond the conventional Born–Markov approximation. The working medium is a two-level system and we drive the tunneling as well as the coupling to one bath with the same period. We identify four different operating regimes of our machine which include a heat engine and a refrigerator. As the coupling strength with one bath is increased, the refrigerator regime disappears, the heat engine regime narrows and their efficiency and coefficient of performance decrease. Furthermore, our model can reproduce the setup of laser cooling of trapped ions in a specific parameter limit.

Performance Analysis of Stirling Engine-Driven Vapor Compression Heat Pump System

NASA Astrophysics Data System (ADS)

Kagawa, Noboru

Stirling engine-driven vapor compression systems have many unique advantages including higher thermal efficiencies, preferable exhaust gas characteristics, multi-fuel usage, and low noise and vibration which can play an important role in alleviating environmental and energy problems. This paper introduces a design method for the systems based on reliable mathematical methods for Stirling and Rankin cycles using reliable thermophysical information for refrigerants. The model deals with a combination of a kinematic Stirling engine and a scroll compressor. Some experimental coefficients are used to formulate the model. The obtained results show the performance behavior in detail. The measured performance of the actual system coincides with the calculated results. Furthermore, the calculated results clarify the performance using alternative refrigerants for R-22.

Wess-Zumino and super Yang-Mills theories in D=4 integral superspace

NASA Astrophysics Data System (ADS)

Castellani, L.; Catenacci, R.; Grassi, P. A.

2018-05-01

We reconstruct the action of N = 1 , D = 4 Wess-Zumino and N = 1 , 2 , D = 4 super-Yang-Mills theories, using integral top forms on the supermanifold M^{(.4|4)} . Choosing different Picture Changing Operators, we show the equivalence of their rheonomic and superspace actions. The corresponding supergeometry and integration theory are discussed in detail. This formalism is an efficient tool for building supersymmetric models in a geometrical framework.

Super-Planckian Thermophotovoltaics Without Vacuum Gaps

NASA Astrophysics Data System (ADS)

Mirmoosa, M. S.; Biehs, S.-A.; Simovski, C. R.

2017-11-01

We introduce the concept of a thermophotovoltaic system whose emitter is separated from the photovoltaic cell by an intermediate thick slab of gallium arsenide. Owing to the engineered structure of the emitter (a multilayer structure of negative- and positive-ɛ layers) together with a high refractiveindex and transparency of the intermediate slab, we achieve a super-Planckian and frequency-selective spectrum of radiative heat transfer which is desirable for the efficient performance of thermophotovoltaic systems.

Status of not-in-kind refrigeration technologies for household space conditioning, water heating and food refrigeration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bansal, Pradeep; Vineyard, Edward Allan; Abdelaziz, Omar

This paper presents a review of the next generation not-in-kind technologies to replace conventional vapor compression refrigeration technology for household applications. Such technologies are sought to provide energy savings or other environmental benefits for space conditioning, water heating and refrigeration for domestic use. These alternative technologies include: thermoacoustic refrigeration, thermoelectric refrigeration, thermotunneling, magnetic refrigeration, Stirling cycle refrigeration, pulse tube refrigeration, Malone cycle refrigeration, absorption refrigeration, adsorption refrigeration, and compressor driven metal hydride heat pumps. Furthermore, heat pump water heating and integrated heat pump systems are also discussed due to their significant energy saving potential for water heating and space conditioningmore » in households. The paper provides a snapshot of the future R&D needs for each of the technologies along with the associated barriers. Both thermoelectric and magnetic technologies look relatively attractive due to recent developments in the materials and prototypes being manufactured.« less

A novel algorithm of super-resolution image reconstruction based on multi-class dictionaries for natural scene

NASA Astrophysics Data System (ADS)

Wu, Wei; Zhao, Dewei; Zhang, Huan

2015-12-01

Super-resolution image reconstruction is an effective method to improve the image quality. It has important research significance in the field of image processing. However, the choice of the dictionary directly affects the efficiency of image reconstruction. A sparse representation theory is introduced into the problem of the nearest neighbor selection. Based on the sparse representation of super-resolution image reconstruction method, a super-resolution image reconstruction algorithm based on multi-class dictionary is analyzed. This method avoids the redundancy problem of only training a hyper complete dictionary, and makes the sub-dictionary more representatives, and then replaces the traditional Euclidean distance computing method to improve the quality of the whole image reconstruction. In addition, the ill-posed problem is introduced into non-local self-similarity regularization. Experimental results show that the algorithm is much better results than state-of-the-art algorithm in terms of both PSNR and visual perception.

High Efficiency Room Air Conditioner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bansal, Pradeep

This project was undertaken as a CRADA project between UT-Battelle and Geberal Electric Company and was funded by Department of Energy to design and develop of a high efficiency room air conditioner. A number of novel elements were investigated to improve the energy efficiency of a state-of-the-art WAC with base capacity of 10,000 BTU/h. One of the major modifications was made by downgrading its capacity from 10,000 BTU/hr to 8,000 BTU/hr by replacing the original compressor with a lower capacity (8,000 BTU/hr) but high efficiency compressor having an EER of 9.7 as compared with 9.3 of the original compressor. However,more » all heat exchangers from the original unit were retained to provide higher EER. The other subsequent major modifications included- (i) the AC fan motor was replaced by a brushless high efficiency ECM motor along with its fan housing, (ii) the capillary tube was replaced with a needle valve to better control the refrigerant flow and refrigerant set points, and (iii) the unit was tested with a drop-in environmentally friendly binary mixture of R32 (90% molar concentration)/R125 (10% molar concentration). The WAC was tested in the environmental chambers at ORNL as per the design rating conditions of AHAM/ASHRAE (Outdoor- 95F and 40%RH, Indoor- 80F, 51.5%RH). All these modifications resulted in enhancing the EER of the WAC by up to 25%.« less

Prototyping an active neutron veto for SuperCDMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calkins, Robert; Loer, Ben

2015-08-17

Neutrons, originating cosmogenically or from radioactive decays, can produce signals in dark matter detectors that are indistinguishable from Weakly Interacting Massive Particles (WIMPs). To combat this background for the SuperCDMS SNOLAB experiment, we are investigating designs for an active neutron veto within the constrained space of the compact SuperCDMS passive shielding. The current design employs an organic liquid scintillator mixed with an agent to enhance thermal neutron captures, with the scintillation light collected using wavelength-shifting fibers and read out by silicon photo-multipliers. We will describe the proposed veto and its predicted efficiency in detail and give some recent results frommore » our R&D and prototyping efforts.« less

Prototyping an Active Neutron Veto for SuperCDMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calkins, Robert; Loer, Ben

2015-08-17

Neutrons, originating cosmogenically or from radioactive decays, can produce signals in dark matter detectors that are indistinguishable from Weakly Interacting Massive Particles (WIMPs). To combat this background for the SuperCDMS SNOLAB experiment, we are investigating designs for an active neutron veto within the constrained space of the compact SuperCDMS passive shielding. The current design employs an organic liquid scintillator mixed with an agent to enhance thermal neutron captures, with the scintillation light collected using wavelength-shifting fibers and read out by silicon photo-multipliers. We will describe the proposed veto and its predicted efficiency in detail and give some recent results frommore » our R&D and prototyping efforts.« less

Proceedings of the 2009 Antenna Applications Symposium, Volume 2

DTIC Science & Technology

2009-12-12

blowers and a heat pipe cold plate. Aspen systems is developing a high efficiency refrigeration based cooling system for cooling dish antenna systems...11.8 301.8 353.0 166.6 308 power amplifier, typically the major heat contributor. Increasing efficiency decreases heat required to be dissipated. This...The size of each array ballooned to a nominal 40 inches on a side and 11-13 inches high. The height was required by the air-air heat exchangers (the

Investigation of an ejector heat pump by analytical methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, C.T.

1984-07-01

Using existing theories of ejector design, the optimum geometry of a high-efficiency ejector - including mixing section cross-sectional area, mass flow entrainment rate, ejector efficiency, and overall COP - for a heat pump cycle was determined. A parametric study was performed to evaluate the COP values for different operating conditions. A sensitivity study determined th effects of nozzle efficiency and diffuser efficiency on the overall ejector heat pump COP. The off-design study estimated the COP for an ejector heat pump operating at off-design conditions. Refrigerants 11, 113, and 114 are three of the halocarbons which best satisfy the criteria formore » an ejector heat pump system. The estimated COPs were 0.3 for the cooling mode and 1.3 for the heating mode at standard operating conditions: a boiler temperature of 93.3/sup 0/C (200/sup 0/F), a condenser temperature of 43.3/sup 0/C (110/sup 0/F), and an evaporator temperature of 10/sup 0/C (50/sup 0/F). Based on the same operating conditions, an optimum ejector geometry was estimated for each of the refrigerants R-11 and R-113. Since the COP values for heating obtained in this analysis are greater than unity, the performance of an ejector heat pump operating in the heating mode should be competitive with that of oil- or gas-fired furnaces or electrical resistance heaters.« less

Miscibility comparison for three refrigerant mixtures and four component refrigerants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, H.M.; Pate, M.B.

1999-07-01

Miscibility data were taken and compared for seven different refrigerants when mixed with the same polyol ester (POE) lubricant. Four of the seven refrigerants were single-component refrigerants while three of the refrigerants were mixtures composed of various combinations of the pure refrigerants. The purpose of this research was to investigate the difference in miscibility characteristics between refrigerant mixtures and their respective component refrigerants. The POE lubricant was a penta erythritol mixed-acid type POE which has a viscosity ISO32. The four pure refrigerants were R-32, R-125, R-134a, and R-143a and the three refrigerant mixtures were R-404A, R407C, and R-410A. The miscibilitymore » tests were performed in a test facility consisting of a series of miniature test cells submerged in a constant temperature bath. The test cells were constructed to allow for complete visibility of the refrigerant/lubricant mixtures under all test conditions. The tests were performed over a concentration range of 0 to 100% and a temperature range of {minus}40 to 194 F. The miscibility test results for refrigerant mixtures are compared to component refrigerants. In all cases, the refrigerant mixtures appear to have better miscibility than their most immiscible pure component.« less

When are solar refrigerators less costly than on-grid refrigerators: A simulation modeling study.

PubMed

Haidari, Leila A; Brown, Shawn T; Wedlock, Patrick; Connor, Diana L; Spiker, Marie; Lee, Bruce Y

2017-04-19

Gavi recommends solar refrigerators for vaccine storage in areas with less than eight hours of electricity per day, and WHO guidelines are more conservative. The question remains: Can solar refrigerators provide value where electrical outages are less frequent? Using a HERMES-generated computational model of the Mozambique routine immunization supply chain, we simulated the use of solar versus electric mains-powered refrigerators (hereafter referred to as "electric refrigerators") at different locations in the supply chain under various circumstances. At their current price premium, the annual cost of each solar refrigerator is 132% more than each electric refrigerator at the district level and 241% more at health facilities. Solar refrigerators provided savings over electric refrigerators when one-day electrical outages occurred more than five times per year at either the district level or the health facilities, even when the electric refrigerator holdover time exceeded the duration of the outage. Two-day outages occurring more than three times per year at the district level or more than twice per year at the health facilities also caused solar refrigerators to be cost saving. Lowering the annual cost of a solar refrigerator to 75% more than an electric refrigerator allowed solar refrigerators to be cost saving at either level when one-day outages occurred more than once per year, or when two-day outages occurred more than once per year at the district level or even once per year at the health facilities. Our study supports WHO and Gavi guidelines. In fact, solar refrigerators may provide savings in total cost per dose administered over electrical refrigerators when electrical outages are less frequent. Our study identified the frequency and duration at which electrical outages need to occur for solar refrigerators to provide savings in total cost per dose administered over electric refrigerators at different solar refrigerator prices. Copyright © 2017. Published by Elsevier Ltd.

A novel electroluminescent PPV copolymer and silsesquioxane nanocomposite film for the preparation of efficient PLED devices.

PubMed

Venegoni, Ivan; Carniato, Fabio; Olivero, Francesco; Bisio, Chiara; Pira, Nello Li; Lambertini, Vito Guido; Marchese, Leonardo

2012-11-02

Polymer light-emitting diodes (PLEDs) have attracted growing interest in recent years for their potential use in displays and lighting fields. Nevertheless, PLED devices have some disadvantages in terms of low optoelectronic efficiency, high cost, short lifetimes and low thermal stability, which limit their final applications. Huge efforts have been made recently to improve the performances of these devices. The addition of inorganic or hybrid organic-inorganic nanoparticles to the light-emitting polymers, for example, allows their thermal stability and electroluminescent efficiency to be increased. Following this approach, novel PLED devices based on composite films of PPV-derivative copolymer (commercial name Super Yellow, SY) and octaisobutil POSS, were developed in this study. The device containing Super Yellow loaded with 1 wt% of POSS showed higher efficiency (ca. +30%) and improved lifetime in comparison to PLED prepared with the pure electroluminescent polymer. The PLED devices developed in this study are suitable candidates for automotive dashboards and, in general, for lighting applications.

Efficiency of super-Eddington magnetically-arrested accretion

NASA Astrophysics Data System (ADS)

McKinney, Jonathan C.; Dai, Lixin; Avara, Mark J.

2015-11-01

The radiative efficiency of super-Eddington accreting black holes (BHs) is explored for magnetically-arrested discs, where magnetic flux builds-up to saturation near the BH. Our three-dimensional general relativistic radiation magnetohydrodynamic (GRRMHD) simulation of a spinning BH (spin a/M = 0.8) accreting at ˜50 times Eddington shows a total efficiency ˜50 per cent when time-averaged and total efficiency ≳ 100 per cent in moments. Magnetic compression by the magnetic flux near the rotating BH leads to a thin disc, whose radiation escapes via advection by a magnetized wind and via transport through a low-density channel created by a Blandford-Znajek (BZ) jet. The BZ efficiency is sub-optimal due to inertial loading of field lines by optically thick radiation, leading to BZ efficiency ˜40 per cent on the horizon and BZ efficiency ˜5 per cent by r ˜ 400rg (gravitational radii) via absorption by the wind. Importantly, radiation escapes at r ˜ 400rg with efficiency η ≈ 15 per cent (luminosity L ˜ 50LEdd), similar to η ≈ 12 per cent for a Novikov-Thorne thin disc and beyond η ≲ 1 per cent seen in prior GRRMHD simulations or slim disc theory. Our simulations show how BH spin, magnetic field, and jet mass-loading affect these radiative and jet efficiencies.

Combined refrigeration system with a liquid pre-cooling heat exchanger

DOEpatents

Gaul, Christopher J.

2003-07-01

A compressor-pump unit for use in a vapor-compression refrigeration system is provided. The compressor-pump unit comprises a driving device including a rotatable shaft. A compressor is coupled with a first portion of the shaft for compressing gaseous refrigerant within the vapor-compression refrigeration system. A liquid pump is coupled with a second portion of the shaft for receiving liquid refrigerant having a first pressure and for discharging the received liquid refrigerant at a second pressure with the second pressure being higher than the first pressure by a predetermined amount such that the discharged liquid refrigerant is subcooled. A pre-cooling circuit is connected to the liquid pump with the pre-cooling circuit being exposed to the gaseous refrigerant whereby the gaseous refrigerant absorbs heat from the liquid refrigerant, prior to the liquid refrigerant entering the liquid pump.

Face Recognition by Metropolitan Police Super-Recognisers.

PubMed

Robertson, David J; Noyes, Eilidh; Dowsett, Andrew J; Jenkins, Rob; Burton, A Mike

2016-01-01

Face recognition is used to prove identity across a wide variety of settings. Despite this, research consistently shows that people are typically rather poor at matching faces to photos. Some professional groups, such as police and passport officers, have been shown to perform just as poorly as the general public on standard tests of face recognition. However, face recognition skills are subject to wide individual variation, with some people showing exceptional ability-a group that has come to be known as 'super-recognisers'. The Metropolitan Police Force (London) recruits 'super-recognisers' from within its ranks, for deployment on various identification tasks. Here we test four working super-recognisers from within this police force, and ask whether they are really able to perform at levels above control groups. We consistently find that the police 'super-recognisers' perform at well above normal levels on tests of unfamiliar and familiar face matching, with degraded as well as high quality images. Recruiting employees with high levels of skill in these areas, and allocating them to relevant tasks, is an efficient way to overcome some of the known difficulties associated with unfamiliar face recognition.

Control method for mixed refrigerant based natural gas liquefier

DOEpatents

Kountz, Kenneth J.; Bishop, Patrick M.

2003-01-01

In a natural gas liquefaction system having a refrigerant storage circuit, a refrigerant circulation circuit in fluid communication with the refrigerant storage circuit, and a natural gas liquefaction circuit in thermal communication with the refrigerant circulation circuit, a method for liquefaction of natural gas in which pressure in the refrigerant circulation circuit is adjusted to below about 175 psig by exchange of refrigerant with the refrigerant storage circuit. A variable speed motor is started whereby operation of a compressor is initiated. The compressor is operated at full discharge capacity. Operation of an expansion valve is initiated whereby suction pressure at the suction pressure port of the compressor is maintained below about 30 psig and discharge pressure at the discharge pressure port of the compressor is maintained below about 350 psig. Refrigerant vapor is introduced from the refrigerant holding tank into the refrigerant circulation circuit until the suction pressure is reduced to below about 15 psig, after which flow of the refrigerant vapor from the refrigerant holding tank is terminated. Natural gas is then introduced into a natural gas liquefier, resulting in liquefaction of the natural gas.

Mountain Plains Learning Experience Guide: Heating, Refrigeration, & Air Conditioning.

ERIC Educational Resources Information Center

Carey, John

This Heating, Refrigeration, and Air Conditioning course is comprised of eleven individualized units: (1) Refrigeration Tools, Materials, and Refrigerant; (2) Basic Heating and Air Conditioning; (3) Sealed System Repairs; (4) Basic Refrigeration Systems; (5) Compression Systems and Compressors; (6) Refrigeration Controls; (7) Electric Circuit…

Energy Efficiency, Water Efficiency, and Renewable Energy Site Assessment: San Juan National Forest - Dolores Ranger District, Colorado

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kandt, Alicen J.; Kiatreungwattana, Kosol

This report summarizes the results from an energy efficiency, water efficiency, and renewable energy site assessment of the Dolores Ranger District in the San Juan National Forest in Colorado. A team led by the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) conducted the assessment with United States Forest Service (USFS) personnel on August 16-17, 2016, as part of ongoing efforts by USFS to reduce energy and water use and implement renewable energy technologies. The assessment is approximately an American Society of Heating, Refrigerating, and Air-Conditioning Engineers Level 2 audit and meets Energy Independence and Security Act requirements.

Measurement and decomposition of energy efficiency of Northeast China-based on super efficiency DEA model and Malmquist index.

PubMed

Ma, Xiaojun; Liu, Yan; Wei, Xiaoxue; Li, Yifan; Zheng, Mengchen; Li, Yudong; Cheng, Chaochao; Wu, Yumei; Liu, Zhaonan; Yu, Yuanbo

2017-08-01

Nowadays, environment problem has become the international hot issue. Experts and scholars pay more and more attention to the energy efficiency. Unlike most studies, which analyze the changes of TFEE in inter-provincial or regional cities, TFEE is calculated with the ratio of target energy value and actual energy input based on data in cities of prefecture levels, which would be more accurate. Many researches regard TFP as TFEE to do analysis from the provincial perspective. This paper is intended to calculate more reliably by super efficiency DEA, observe the changes of TFEE, and analyze its relation with TFP, and it proves that TFP is not equal to TFEE. Additionally, the internal influences of the TFEE are obtained via the Malmquist index decomposition. The external influences of the TFFE are analyzed afterward based on the Tobit models. Analysis results demonstrate that Heilongjiang has the highest TFEE followed by Jilin, and Liaoning has the lowest TFEE. Eventually, some policy suggestions are proposed for the influences of energy efficiency and study results.

Super Boiler: Packed Media/Transport Membrane Boiler Development and Demonstration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liss, William E; Cygan, David F

2013-04-17

Gas Technology Institute (GTI) and Cleaver-Brooks developed a new gas-fired steam generation system the Super Boiler for increased energy efficiency, reduced equipment size, and reduced emissions. The system consists of a firetube boiler with a unique staged furnace design, a two-stage burner system with engineered internal recirculation and inter-stage cooling integral to the boiler, unique convective pass design with extended internal surfaces for enhanced heat transfer, and a novel integrated heat recovery system to extract maximum energy from the flue gas. With these combined innovations, the Super Boiler technical goals were set at 94% HHV fuel efficiency, operation on naturalmore » gas with <5 ppmv NOx (referenced to 3%O2), and 50% smaller than conventional boilers of similar steam output. To demonstrate these technical goals, the project culminated in the industrial demonstration of this new high-efficiency technology on a 300 HP boiler at Clement Pappas, a juice bottler located in Ontario, California. The Super Boiler combustion system is based on two stage combustion which combines air staging, internal flue gas recirculation, inter-stage cooling, and unique fuel-air mixing technology to achieve low emissions rather than external flue gas recirculation which is most commonly used today. The two-stage combustion provides lower emissions because of the integrated design of the boiler and combustion system which permit precise control of peak flame temperatures in both primary and secondary stages of combustion. To reduce equipment size, the Super Boiler's dual furnace design increases radiant heat transfer to the furnace walls, allowing shorter overall furnace length, and also employs convective tubes with extended surfaces that increase heat transfer by up to 18-fold compared to conventional bare tubes. In this way, a two-pass boiler can achieve the same efficiency as a traditional three or four-pass firetube boiler design. The Super Boiler is consequently up to 50% smaller in footprint, has a smaller diameter, and is up to 50% lower in weight, resulting in very compact design with reduced material cost and labor costs, while requiring less boiler room floor space. For enhanced energy efficiency, the heat recovery system uses a transport membrane condenser (TMC), a humidifying air heater (HAH), and a split-stage economizer to extract maximum energy from the flue gas. The TMC is a new innovation that pulls a major portion of water vapor produced by the combustion process from the flue gases along with its sensible and latent heat. This results in nearly 100% transfer of heat to the boiler feed water. The HAH improves the effectiveness of the TMC, particularly in steam systems that do not have a large amount of cold makeup water. In addition, the HAH humidifies the combustion air to reduce NOx formation. The split-stage economizer preheats boiler feed water in the same way as a conventional economizer, but extracts more heat by working in tandem with the TMC and HAH to reduce flue gas temperature. These components are designed to work synergistically to achieve energy efficiencies of 92-94% which is 10-15% higher than today's typical firetube boilers.« less

Refrigerant directly cooled capacitors

DOEpatents

Hsu, John S [Oak Ridge, TN; Seiber, Larry E [Oak Ridge, TN; Marlino, Laura D [Oak Ridge, TN; Ayers, Curtis W [Kingston, TN

2007-09-11

The invention is a direct contact refrigerant cooling system using a refrigerant floating loop having a refrigerant and refrigeration devices. The cooling system has at least one hermetic container disposed in the refrigerant floating loop. The hermetic container has at least one electronic component selected from the group consisting of capacitors, power electronic switches and gating signal module. The refrigerant is in direct contact with the electronic component.

Achieving high-efficiency emission depletion nanoscopy by employing cross relaxation in upconversion nanoparticles.

PubMed

Zhan, Qiuqiang; Liu, Haichun; Wang, Baoju; Wu, Qiusheng; Pu, Rui; Zhou, Chao; Huang, Bingru; Peng, Xingyun; Ågren, Hans; He, Sailing

2017-10-20

Stimulated emission depletion microscopy provides a powerful sub-diffraction imaging modality for life science studies. Conventionally, stimulated emission depletion requires a relatively high light intensity to obtain an adequate depletion efficiency through only light-matter interaction. Here we show efficient emission depletion for a class of lanthanide-doped upconversion nanoparticles with the assistance of interionic cross relaxation, which significantly lowers the laser intensity requirements of optical depletion. We demonstrate two-color super-resolution imaging using upconversion nanoparticles (resolution ~ 66 nm) with a single pair of excitation/depletion beams. In addition, we show super-resolution imaging of immunostained cytoskeleton structures of fixed cells (resolution ~ 82 nm) using upconversion nanoparticles. These achievements provide a new perspective for the development of photoswitchable luminescent probes and will broaden the applications of lanthanide-doped nanoparticles for sub-diffraction microscopic imaging.

Inferring Biological Structures from Super-Resolution Single Molecule Images Using Generative Models

PubMed Central

Maji, Suvrajit; Bruchez, Marcel P.

2012-01-01

Localization-based super resolution imaging is presently limited by sampling requirements for dynamic measurements of biological structures. Generating an image requires serial acquisition of individual molecular positions at sufficient density to define a biological structure, increasing the acquisition time. Efficient analysis of biological structures from sparse localization data could substantially improve the dynamic imaging capabilities of these methods. Using a feature extraction technique called the Hough Transform simple biological structures are identified from both simulated and real localization data. We demonstrate that these generative models can efficiently infer biological structures in the data from far fewer localizations than are required for complete spatial sampling. Analysis at partial data densities revealed efficient recovery of clathrin vesicle size distributions and microtubule orientation angles with as little as 10% of the localization data. This approach significantly increases the temporal resolution for dynamic imaging and provides quantitatively useful biological information. PMID:22629348

A simple way to achieve bioinspired hybrid wettability surface with micro/nanopatterns for efficient fog collection.

PubMed

Yin, Kai; Du, Haifeng; Dong, Xinran; Wang, Cong; Duan, Ji-An; He, Jun

2017-10-05

Fog collection is receiving increasing attention for providing water in semi-arid deserts and inland areas. Inspired by the fog harvesting ability of the hydrophobic-hydrophilic surface of Namib desert beetles, we present a simple, low-cost method to prepare a hybrid superhydrophobic-hydrophilic surface. The surface contains micro/nanopatterns, and is prepared by incorporating femtosecond-laser fabricated polytetrafluoroethylene nanoparticles deposited on superhydrophobic copper mesh with a pristine hydrophilic copper sheet. The as-prepared surface exhibits enhanced fog collection efficiency compared with uniform (super)hydrophobic or (super)hydrophilic surfaces. This enhancement can be tuned by controlling the mesh number, inclination angle, and fabrication structure. Moreover, the surface shows excellent anti-corrosion ability after immersing in 1 M HCl, 1 M NaOH, and 10 wt% NaCl solutions for 2 hours. This work may provide insight into fabricating hybrid superhydrophobic-hydrophilic surfaces for efficient atmospheric water collection.

Super Energy Efficiency Design (S.E.E.D.) Home Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

German, A.; Dakin, B.; Backman, C.

This report describes the results of evaluation by the Alliance for Residential Building Innovation (ARBI) Building America team of the 'Super Energy Efficient Design' (S.E.E.D) home, a 1,935 sq. ft., single-story spec home located in Tucson, AZ. This prototype design was developed with the goal of providing an exceptionally energy efficient yet affordable home and includes numerous aggressive energy features intended to significantly reduce heating and cooling loads such as structural insulated panel (SIP) walls and roof, high performance windows, an ERV, an air-to-water heat pump with mixed-mode radiant and forced air delivery, solar water heating, and rooftop PV. Sourcemore » energy savings are estimated at 45% over the Building America B10 Benchmark. System commissioning, short term testing, long term monitoring and detailed analysis of results was conducted to identify the performance attributes and cost effectiveness of the whole house measure package.« less

Super Energy Efficient Design (S.E.E.D.) Home Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

German, A.; Dakin, B.; Backman, C.

This report describes the results of evaluation by the Alliance for Residential Building Innovation (ARBI) Building America team of the “Super Energy Efficient Design” (S.E.E.D) home, a 1,935 sq. ft., single-story spec home located in Tucson, AZ. This prototype design was developed with the goal of providing an exceptionally energy efficient yet affordable home and includes numerous aggressive energy features intended to significantly reduce heating and cooling loads such as structural insulated panel (SIP) walls and roof, high performance windows, an ERV, an air-to-water heat pump with mixed-mode radiant and forced air delivery, solar water heating, and rooftop PV. Sourcemore » energy savings are estimated at 45% over the Building America B10 Benchmark. System commissioning, short term testing, long term monitoring and detailed analysis of results was conducted to identify the performance attributes and cost effectiveness of the whole house measure package.« less

Image reconstructions from super-sampled data sets with resolution modeling in PET imaging.

PubMed

Li, Yusheng; Matej, Samuel; Metzler, Scott D

2014-12-01

Spatial resolution in positron emission tomography (PET) is still a limiting factor in many imaging applications. To improve the spatial resolution for an existing scanner with fixed crystal sizes, mechanical movements such as scanner wobbling and object shifting have been considered for PET systems. Multiple acquisitions from different positions can provide complementary information and increased spatial sampling. The objective of this paper is to explore an efficient and useful reconstruction framework to reconstruct super-resolution images from super-sampled low-resolution data sets. The authors introduce a super-sampling data acquisition model based on the physical processes with tomographic, downsampling, and shifting matrices as its building blocks. Based on the model, we extend the MLEM and Landweber algorithms to reconstruct images from super-sampled data sets. The authors also derive a backprojection-filtration-like (BPF-like) method for the super-sampling reconstruction. Furthermore, they explore variant methods for super-sampling reconstructions: the separate super-sampling resolution-modeling reconstruction and the reconstruction without downsampling to further improve image quality at the cost of more computation. The authors use simulated reconstruction of a resolution phantom to evaluate the three types of algorithms with different super-samplings at different count levels. Contrast recovery coefficient (CRC) versus background variability, as an image-quality metric, is calculated at each iteration for all reconstructions. The authors observe that all three algorithms can significantly and consistently achieve increased CRCs at fixed background variability and reduce background artifacts with super-sampled data sets at the same count levels. For the same super-sampled data sets, the MLEM method achieves better image quality than the Landweber method, which in turn achieves better image quality than the BPF-like method. The authors also demonstrate that the reconstructions from super-sampled data sets using a fine system matrix yield improved image quality compared to the reconstructions using a coarse system matrix. Super-sampling reconstructions with different count levels showed that the more spatial-resolution improvement can be obtained with higher count at a larger iteration number. The authors developed a super-sampling reconstruction framework that can reconstruct super-resolution images using the super-sampling data sets simultaneously with known acquisition motion. The super-sampling PET acquisition using the proposed algorithms provides an effective and economic way to improve image quality for PET imaging, which has an important implication in preclinical and clinical region-of-interest PET imaging applications.

Refrigerant charge management in a heat pump water heater

DOEpatents

Chen, Jie; Hampton, Justin W.

2014-06-24

Heat pumps that heat or cool a space and that also heat water, refrigerant management systems for such heat pumps, methods of managing refrigerant charge, and methods for heating and cooling a space and heating water. Various embodiments deliver refrigerant gas to a heat exchanger that is not needed for transferring heat, drive liquid refrigerant out of that heat exchanger, isolate that heat exchanger against additional refrigerant flowing into it, and operate the heat pump while the heat exchanger is isolated. The heat exchanger can be isolated by closing an electronic expansion valve, actuating a refrigerant management valve, or both. Refrigerant charge can be controlled or adjusted by controlling how much liquid refrigerant is driven from the heat exchanger, by letting refrigerant back into the heat exchanger, or both. Heat pumps can be operated in different modes of operation, and segments of refrigerant conduit can be interconnected with various components.

Refrigeration oils for low GWP refrigerants in various applications

NASA Astrophysics Data System (ADS)

Saito, R.; Sundaresan, S. G.

2017-08-01

The practical use of the refrigeration systems is considered as a methods to suppress global warming. The replacement of a refrigerant with a new one that has lower global warming potential (GWP) has been underway for several years. For the application fields of refrigerators, domestic air conditioners, automotive air conditioners and hot water dispensers, the investigation has almost finished. It is still underway for the application fields of commercial air conditioners and chillers, refrigeration facilities for cold storage, etc. And now, the refrigeration system is being applied in various ways to decrease global warming above the generation of electric power with organic Rankine cycle, the binary electric generation with ground source heat pump, and so on. In these situations, various refrigerants are developed and several kinds of suitable refrigeration oils are selected. This paper presents the consideration of suitable refrigeration oil for the various low GWP refrigerants.

Techno-Economic Analysis of Indian Draft Standard Levels for RoomAir Conditioners

DOE Office of Scientific and Technical Information (OSTI.GOV)

McNeil, Michael A.; Iyer, Maithili

The Indian Bureau of Energy Efficiency (BEE) finalized its first set of efficiency standards and labels for room air conditioners in July of 2006. These regulations followed soon after the publication of levels for frost-free refrigerators in the same year. As in the case of refrigerators, the air conditioner program introduces Minimum Efficiency Performance Standards (MEPS) and comparative labels simultaneously, with levels for one to five stars. Also like the refrigerator program, BEE defined several successive program phases of increasing stringency. In support of BEE's refrigerator program, Lawrence Berkeley National Laboratory (LBNL) produced an analysis of national impacts of standardsmore » in collaboration with the Collaborative Labeling and Standards Program (CLASP). That analysis drew on LBNL's experience with standards programs in the United States, as well as many other countries. Subsequently, as part of the process for setting optimal levels for air conditioner regulations, CLASP commissioned LBNL to provide support to BEE in the form of a techno-economic evaluation of air conditioner efficiency technologies. This report describes the methodology and results of this techno-economic evaluation. The analysis consists of three components: (1) Cost effectiveness to consumers of efficiency technologies relative to current baseline. (2) Impacts on the current market from efficiency regulations. (3) National energy and financial impacts. The analysis relied on detailed and up-to-date technical data made available by BEE and industry representatives. Technical parameters were used in conjunction with knowledge about air conditioner use patterns in the residential and commercial sectors, and prevailing marginal electricity prices, in order to give an estimate of per-unit financial impacts. In addition, the overall impact of the program was evaluated by combining unit savings with market forecasts in order to yield national impacts. LBNL presented preliminary results of these analyses in May 2006, at a meeting of BEEs Technical Committee for Air Conditioners. This meeting was attended by a wide array of stakeholder, including industry representatives, engineers and consumer advocates. Comments made by stakeholders at this meeting are incorporated into the final analysis presented in this report. The current analysis begins with the Rating Plan drafted by BEE in 2006, along with an evaluation of the market baseline according to test data submitted by manufacturers. MEPS, label rating levels, and baseline efficiencies are presented in Section 2. First, we compare Indian MEPS with current standards in other countries, and assess their relative stringency. Baseline efficiencies are then used to estimate the fraction of models likely to remain on the market at each phase of the program, and the impact on market-weighted efficiency levels. Section 3 deals with cost-effectiveness of higher efficiency design options. The cost-benefit analysis is grounded in technical parameters provided by industry representatives in India. This data allows for an assessment of financial costs and benefits to consumers as a result of the standards and labeling program. A Life-Cycle Cost (LCC) calculation is used to evaluate the impacts of the program at the unit level, thus providing some insight into the appropriateness of the levels chosen, and additional opportunities for further ratcheting. In addition to LCC, we also calculate payback periods, cost of conserved energy (CCE), and return on investment (ROI). Finally, Section 4 covers national impacts. This is an extension of unit level estimates in the two previous sections. Extrapolation to the national level depends on a forecast of air conditioner purchases (shipments), which we describe here. Following the cost-benefit analysis, we construct several efficiency scenarios including the BEE plan, but also considering further potential for efficiency improvement. These are combined with shipments through a stock accounting model in order to forecast air conditioner energy consumption in each scenario, and associated electricity savings and carbon emission mitigation. Finally, financial costs and savings are scaled to the national level to evaluate net fiscal benefits.« less

When are solar refrigerators less costly than on-grid refrigerators: A simulation modeling study☆

PubMed Central

Haidari, Leila A.; Brown, Shawn T.; Wedlock, Patrick; Connor, Diana L.; Spiker, Marie; Lee, Bruce Y.

2017-01-01

Background Gavi recommends solar refrigerators for vaccine storage in areas with less than eight hours of electricity per day, and WHO guidelines are more conservative. The question remains: Can solar refrigerators provide value where electrical outages are less frequent? Methods Using a HERMES-generated computational model of the Mozambique routine immunization supply chain, we simulated the use of solar versus electric mains-powered refrigerators (hereafter referred to as “electric refrigerators”) at different locations in the supply chain under various circumstances. Results At their current price premium, the annual cost of each solar refrigerator is 132% more than each electric refrigerator at the district level and 241% more at health facilities. Solar refrigerators provided savings over electric refrigerators when one-day electrical outages occurred more than five times per year at either the district level or the health facilities, even when the electric refrigerator holdover time exceeded the duration of the outage. Two-day outages occurring more than three times per year at the district level or more than twice per year at the health facilities also caused solar refrigerators to be cost saving. Lowering the annual cost of a solar refrigerator to 75% more than an electric refrigerator allowed solar refrigerators to be cost saving at either level when one-day outages occurred more than once per year, or when two-day outages occurred more than once per year at the district level or even once per year at the health facilities. Conclusion Our study supports WHO and Gavi guidelines. In fact, solar refrigerators may provide savings in total cost per dose administered over electrical refrigerators when electrical outages are less frequent. Our study identified the frequency and duration at which electrical outages need to occur for solar refrigerators to provide savings in total cost per dose administered over electric refrigerators at different solar refrigerator prices. PMID:28364935

The Future of Air Conditioning for Buildings - Executive Summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goetzler, William; Guernsey, Matt; Young, J.

2016-07-01

The Building Technologies Office (BTO), within the U.S. Department of Energy’s (DOE) Office of Energy Efficiency and Renewable Energy, works with researchers and industry to develop and deploy technologies that can substantially reduce energy consumption and greenhouse gas (GHG) emissions in residential and commercial buildings. Air conditioning (A/C) systems in buildings contribute to GHG emissions both directly through refrigerant emissions, as well as indirectly through fossil fuel combustion for power generation. BTO promotes pre-competitive research and development (R&D) on next-generation HVAC technologies that support the phase down of hydrofluorocarbon (HFC) production and consumption, as well as cost-effective energy efficiency improvements.more » Over the past several decades, product costs and lifecycle cooling costs have declined substantially in many global markets due to improved, higher-volume manufacturing and higher energy efficiency driven by R&D investments and efficiency policies including minimum efficiency standards and labeling programs.1 This report characterizes the current landscape and trends in the global A/C market, including discussion of both direct and indirect climate impacts, and potential global warming impacts from growing global A/C usage. The report also documents solutions that can help achieve international goals for energy efficiency and GHG emissions reductions. The solutions include pathways related to low-global warming potential2 (GWP) refrigerants, energy efficiency innovations, long-term R&D initiatives, and regulatory actions. DOE provides, with this report, a fact-based vision for the future of A/C use around the world. DOE intends for this vision to reflect a broad and balanced aggregation of perspectives. DOE brings together this content in an effort to support dialogue within the international community and help keep key facts and objectives at the forefront among the many important discussions.« less

Model based multivariable controller for large scale compression stations. Design and experimental validation on the LHC 18KW cryorefrigerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonne, François; Bonnay, Patrick; Alamir, Mazen

2014-01-29

In this paper, a multivariable model-based non-linear controller for Warm Compression Stations (WCS) is proposed. The strategy is to replace all the PID loops controlling the WCS with an optimally designed model-based multivariable loop. This new strategy leads to high stability and fast disturbance rejection such as those induced by a turbine or a compressor stop, a key-aspect in the case of large scale cryogenic refrigeration. The proposed control scheme can be used to have precise control of every pressure in normal operation or to stabilize and control the cryoplant under high variation of thermal loads (such as a pulsedmore » heat load expected to take place in future fusion reactors such as those expected in the cryogenic cooling systems of the International Thermonuclear Experimental Reactor ITER or the Japan Torus-60 Super Advanced fusion experiment JT-60SA). The paper details how to set the WCS model up to synthesize the Linear Quadratic Optimal feedback gain and how to use it. After preliminary tuning at CEA-Grenoble on the 400W@1.8K helium test facility, the controller has been implemented on a Schneider PLC and fully tested first on the CERN's real-time simulator. Then, it was experimentally validated on a real CERN cryoplant. The efficiency of the solution is experimentally assessed using a reasonable operating scenario of start and stop of compressors and cryogenic turbines. This work is partially supported through the European Fusion Development Agreement (EFDA) Goal Oriented Training Program, task agreement WP10-GOT-GIRO.« less

Development of transition edge sensors with rf-SQUID based multiplexing system for the HOLMES experiment

NASA Astrophysics Data System (ADS)

Puiu, A.; Becker, D.; Bennett, D.; Faverzani, M.; Ferri, E.; Fowler, J.; Gard, J.; Hays-Wehle, J.; Hilton, G.; Giachero, A.; Maino, M.; Mates, J.; Nucciotti, A.; Schmidt, D.; Swetz, D.; Ullom, J.; Vale, L.

2017-09-01

Measuring the neutrino mass is one the most compelling issue in particle physics. HOLMES is an experiment funded by the European Research Council for a direct measurement of neutrino mass. HOLMES will perform a precise measurement of the end point of the Electron Capture decay spectrum of 163Ho in order to extract information on neutrino mass with a sensitivity as low as 1 eV. HOLMES, in its final configuration will deploy a 1000 pixel array of low temperature microcalorimeters: each calorimeter consists of an absorber, where the Ho atoms will be implanted, coupled to a Transition Edge Sensor thermometer. The detectors will be kept at the working temperature of ˜70 mK using a dilution refrigerator. In order to gather the required 3 × 1013 events in a three year long data taking with a pile up fraction as low as 10-4, detectors must fulfill rather high speed and resolution requirements, i.e. 10 µs rise time and 4 eV resolution. To ensure such performances with an efficient read out technique for very large detectors array kept at low temperature inside a cryostat is no trivial matter: at the moment, the most appealing read out technique applicable to large arrays of Transition Edge Sensors is rf-SQUID multiplexing. It is based on the use of rf-SQUIDs as input devices with flux ramp modulation for linearisation purposes; the rf-SQUID is then coupled to a super-conductive λ/4-wave resonator in the GHz range, and the modulated signal is finally read out using the homodyne technique.

Model based multivariable controller for large scale compression stations. Design and experimental validation on the LHC 18KW cryorefrigerator

NASA Astrophysics Data System (ADS)

Bonne, François; Alamir, Mazen; Bonnay, Patrick; Bradu, Benjamin

2014-01-01

In this paper, a multivariable model-based non-linear controller for Warm Compression Stations (WCS) is proposed. The strategy is to replace all the PID loops controlling the WCS with an optimally designed model-based multivariable loop. This new strategy leads to high stability and fast disturbance rejection such as those induced by a turbine or a compressor stop, a key-aspect in the case of large scale cryogenic refrigeration. The proposed control scheme can be used to have precise control of every pressure in normal operation or to stabilize and control the cryoplant under high variation of thermal loads (such as a pulsed heat load expected to take place in future fusion reactors such as those expected in the cryogenic cooling systems of the International Thermonuclear Experimental Reactor ITER or the Japan Torus-60 Super Advanced fusion experiment JT-60SA). The paper details how to set the WCS model up to synthesize the Linear Quadratic Optimal feedback gain and how to use it. After preliminary tuning at CEA-Grenoble on the 400W@1.8K helium test facility, the controller has been implemented on a Schneider PLC and fully tested first on the CERN's real-time simulator. Then, it was experimentally validated on a real CERN cryoplant. The efficiency of the solution is experimentally assessed using a reasonable operating scenario of start and stop of compressors and cryogenic turbines. This work is partially supported through the European Fusion Development Agreement (EFDA) Goal Oriented Training Program, task agreement WP10-GOT-GIRO.

Dual Super-Systolic Core for Real-Time Reconstructive Algorithms of High-Resolution Radar/SAR Imaging Systems

PubMed Central

Atoche, Alejandro Castillo; Castillo, Javier Vázquez

2012-01-01

A high-speed dual super-systolic core for reconstructive signal processing (SP) operations consists of a double parallel systolic array (SA) machine in which each processing element of the array is also conceptualized as another SA in a bit-level fashion. In this study, we addressed the design of a high-speed dual super-systolic array (SSA) core for the enhancement/reconstruction of remote sensing (RS) imaging of radar/synthetic aperture radar (SAR) sensor systems. The selected reconstructive SP algorithms are efficiently transformed in their parallel representation and then, they are mapped into an efficient high performance embedded computing (HPEC) architecture in reconfigurable Xilinx field programmable gate array (FPGA) platforms. As an implementation test case, the proposed approach was aggregated in a HW/SW co-design scheme in order to solve the nonlinear ill-posed inverse problem of nonparametric estimation of the power spatial spectrum pattern (SSP) from a remotely sensed scene. We show how such dual SSA core, drastically reduces the computational load of complex RS regularization techniques achieving the required real-time operational mode. PMID:22736964

Magnetic Refrigeration Development

NASA Technical Reports Server (NTRS)

Deardoff, D. D.; Johnson, D. L.

1984-01-01

Magnetic refrigeration is being developed to determine whether it may be used as an alternative to the Joule-Thomson circuit of a closed cycle refrigerator for providing 4 K refrigeration. An engineering model 4-15 K magnetic refrigerator has been designed and is being fabricated. This article describes the overall design of the magnetic refrigerator.

Non-intrusive refrigerant charge indicator

DOEpatents

Mei, Viung C.; Chen, Fang C.; Kweller, Esher

2005-03-22

A non-intrusive refrigerant charge level indicator includes a structure for measuring at least one temperature at an outside surface of a two-phase refrigerant line section. The measured temperature can be used to determine the refrigerant charge status of an HVAC system, and can be converted to a pressure of the refrigerant in the line section and compared to a recommended pressure range to determine whether the system is under-charged, properly charged or over-charged. A non-intrusive method for assessing the refrigerant charge level in a system containing a refrigerant fluid includes the step of measuring a temperature at least one outside surface of a two-phase region of a refrigerant containing refrigerant line, wherein the temperature measured can be converted to a refrigerant pressure within the line section.

78 FR 25724 - Petition for Waiver of GE Appliances From the Department of Energy Residential Refrigerator and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-02

... procedures that are reasonably designed to produce results that measure the energy efficiency, energy use, or... contains one or more design characteristics that prevents testing of the basic model according to the... unrepresentative of its true energy consumption characteristics as to provide materially inaccurate comparative...

High-Performance Computing Data Center | Computational Science | NREL

Science.gov Websites

liquid cooling to achieve its very low PUE, then captures and reuses waste heat as the primary heating dry cooler that uses refrigerant in a passive cycle to dissipate heat-is reducing onsite water Measuring efficiency through PUE Warm-water liquid cooling Re-using waste heat from computing components

Dullgren extraction of soil mites (Acarina): Effect of refrigeration time on extraction efficiency

Treesearch

Michelle B. Lakly; D.A. Crossley

2000-01-01

Soil microarthropods constitute one of the most species rich communities in . forest ecosystems (Crossley & Blair, 1991). The effects of soil fauna in these systems on decomposition rates, nutrient regeneration and soil structure have been well documented; however, dependable estimates of population size and community structure largely depend upon adequate sampling...

Reversible and irreversible heat engine and refrigerator cycles

NASA Astrophysics Data System (ADS)

Leff, Harvey S.

2018-05-01

Although no reversible thermodynamic cycles exist in nature, nearly all cycles covered in textbooks are reversible. This is a review, clarification, and extension of results and concepts for quasistatic, reversible and irreversible processes and cycles, intended primarily for teachers and students. Distinctions between the latter process types are explained, with emphasis on clockwise (CW) and counterclockwise (CCW) cycles. Specific examples of each are examined, including Carnot, Kelvin and Stirling cycles. For the Stirling cycle, potentially useful task-specific efficiency measures are proposed and illustrated. Whether a cycle behaves as a traditional refrigerator or heat engine can depend on whether it is reversible or irreversible. Reversible and irreversible-quasistatic CW cycles both satisfy Carnot's inequality for thermal efficiency, η ≤ η C a r n o t . Irreversible CCW cycles with two reservoirs satisfy the coefficient of performance inequality K ≤ K C a r n o t . However, an arbitrary reversible cycle satisfies K ≥ K C a r n o t when compared with a reversible Carnot cycle operating between its maximum and minimum temperatures, a potentially counterintuitive result.

Waiting time effect of a GM type orifice pulse tube refrigerator

NASA Astrophysics Data System (ADS)

Zhu, Shaowei; Kakimi, Yasuhiro; Matsubara, Yoichi

In a general GM type orifice pulse tube refrigerator, there are two short periods during which both the high pressure valve and the low pressure valve are closed in one cycle. We call the short period `waiting time'. The pressure differences across the high pressure valve and the low pressure valve are decreased by using long waiting time. The pressure difference loss is decreased. Thus, the cooling capacity and the efficiency are increased, and the no-load temperature is decreased. The mechanism of the waiting time is discussed with numerical analysis and verified by experiments. Experiments show that there is an optimum waiting time for the no-load temperature, the cooling capacity and the efficiency, respectively. The no-load temperature of 40.3 K was achieved with a 90° waiting time. The cooling capacity of 58 W at 80 K was achieved with a 60° waiting time. The no-load temperature of 45.1 K and the cooling capacity of 45 W at 80 K were achieved with a 1° waiting time.

Super-resolution image reconstruction from UAS surveillance video through affine invariant interest point-based motion estimation

NASA Astrophysics Data System (ADS)

He, Qiang; Schultz, Richard R.; Wang, Yi; Camargo, Aldo; Martel, Florent

2008-01-01

In traditional super-resolution methods, researchers generally assume that accurate subpixel image registration parameters are given a priori. In reality, accurate image registration on a subpixel grid is the single most critically important step for the accuracy of super-resolution image reconstruction. In this paper, we introduce affine invariant features to improve subpixel image registration, which considerably reduces the number of mismatched points and hence makes traditional image registration more efficient and more accurate for super-resolution video enhancement. Affine invariant interest points include those corners that are invariant to affine transformations, including scale, rotation, and translation. They are extracted from the second moment matrix through the integration and differentiation covariance matrices. Our tests are based on two sets of real video captured by a small Unmanned Aircraft System (UAS) aircraft, which is highly susceptible to vibration from even light winds. The experimental results from real UAS surveillance video show that affine invariant interest points are more robust to perspective distortion and present more accurate matching than traditional Harris/SIFT corners. In our experiments on real video, all matching affine invariant interest points are found correctly. In addition, for the same super-resolution problem, we can use many fewer affine invariant points than Harris/SIFT corners to obtain good super-resolution results.

Single-shot and single-sensor high/super-resolution microwave imaging based on metasurface

PubMed Central

Wang, Libo; Li, Lianlin; Li, Yunbo; Zhang, Hao Chi; Cui, Tie Jun

2016-01-01

Real-time high-resolution (including super-resolution) imaging with low-cost hardware is a long sought-after goal in various imaging applications. Here, we propose broadband single-shot and single-sensor high-/super-resolution imaging by using a spatio-temporal dispersive metasurface and an imaging reconstruction algorithm. The metasurface with spatio-temporal dispersive property ensures the feasibility of the single-shot and single-sensor imager for super- and high-resolution imaging, since it can convert efficiently the detailed spatial information of the probed object into one-dimensional time- or frequency-dependent signal acquired by a single sensor fixed in the far-field region. The imaging quality can be improved by applying a feature-enhanced reconstruction algorithm in post-processing, and the desired imaging resolution is related to the distance between the object and metasurface. When the object is placed in the vicinity of the metasurface, the super-resolution imaging can be realized. The proposed imaging methodology provides a unique means to perform real-time data acquisition, high-/super-resolution images without employing expensive hardware (e.g. mechanical scanner, antenna array, etc.). We expect that this methodology could make potential breakthroughs in the areas of microwave, terahertz, optical, and even ultrasound imaging. PMID:27246668

Super-Nyquist shaping and processing technologies for high-spectral-efficiency optical systems

NASA Astrophysics Data System (ADS)

Jia, Zhensheng; Chien, Hung-Chang; Zhang, Junwen; Dong, Ze; Cai, Yi; Yu, Jianjun

2013-12-01

The implementations of super-Nyquist pulse generation, both in a digital field using a digital-to-analog converter (DAC) or an optical filter at transmitter side, are introduced. Three corresponding signal processing algorithms at receiver are presented and compared for high spectral-efficiency (SE) optical systems employing the spectral prefiltering. Those algorithms are designed for the mitigation towards inter-symbol-interference (ISI) and inter-channel-interference (ICI) impairments by the bandwidth constraint, including 1-tap constant modulus algorithm (CMA) and 3-tap maximum likelihood sequence estimation (MLSE), regular CMA and digital filter with 2-tap MLSE, and constant multi-modulus algorithm (CMMA) with 2-tap MLSE. The principles and prefiltering tolerance are given through numerical and experimental results.

Thermoelectric refrigerator having improved temperature stabilization means

DOEpatents

Falco, Charles M.

1982-01-01

A control system for thermoelectric refrigerators is disclosed. The thermoelectric refrigerator includes at least one thermoelectric element that undergoes a first order change at a predetermined critical temperature. The element functions as a thermoelectric refrigerator element above the critical temperature, but discontinuously ceases to function as a thermoelectric refrigerator element below the critical temperature. One example of such an arrangement includes thermoelectric refrigerator elements which are superconductors. The transition temperature of one of the superconductor elements is selected as the temperature control point of the refrigerator. When the refrigerator attempts to cool below the point, the metals become superconductors losing their ability to perform as a thermoelectric refrigerator. An extremely accurate, first-order control is realized.

The Formation of Super-Earths by Tidally Forced Turbulence

NASA Astrophysics Data System (ADS)

Yu, Cong

2017-12-01

The Kepler observations indicate that many exoplanets are super-Earths, which brings about a puzzle for the core-accretion scenario. Since observed super-Earths are in the range of critical mass, they accrete gas efficiently and become gas giants. Theoretically, super-Earths are predicted to be rare in the core-accretion framework. To resolve this contradiction, we propose that the tidally forced turbulent diffusion may affect the heat transport inside the planet. Thermal feedback induced by turbulent diffusion is investigated. We find that the tidally forced turbulence generates pseudo-adiabatic regions within radiative zones, which pushes the radiative-convective boundaries inward. This decreases the cooling luminosity and enhances the Kelvin-Helmholtz (KH) timescale. For a given lifetime of protoplanetary disks (PPDs), there exists a critical threshold for the turbulent diffusivity, ν critical. If ν turb > ν critical, the KH timescale is longer than the disk lifetime and the planet becomes a super-Earth, rather than a gas giant. We find that even a small value of turbulent diffusion has influential effects on the evolution of super-Earths. The ν critical increases with the core mass. We further ascertain that, within the minimum-mass extrasolar nebula, ν critical increases with the semimajor axis. This may explain the feature that super-Earths are common in inner PPD regions, while gas giants are common in outer PPD regions. The predicted envelope mass fraction is not fully consistent with observations. We discuss physical processes, such as late core assembly and mass-loss mechanisms, that may be operating during super-Earth formation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salasovich, James; LoVullo, David; Kandt, Alicen

This report summarizes results from the energy efficiency, water efficiency, and renewable energy site assessment of the Mendenhall Glacier Visitor Center and site in Juneau, Alaska. The assessment is an American Society of Heating, Refrigerating, and Air-Conditioning Engineers Level 2 audit and meets Energy Independence and Security Act requirements. A team led by the U.S. Department of Energy's National Renewable Energy Laboratory conducted the assessment with U.S. Forest Service personnel August 19-20, 2015, as part of ongoing efforts by USFS to reduce energy and water use.

Performance monitoring can boost turboexpander efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

McIntire, R.

1982-07-05

Focuses on the turboexpander/refrigeration system's radial expander and radial compressor. Explains that radial expander efficiency depends on mass flow rate, inlet pressure, inlet temperature, discharge pressure, gas composition, and shaft speed. Discusses quantifying the performance of the separate components over a range of operating conditions; estimating the increase in performance associated with any hardware change; and developing an analytical (computer) model of the entire system by using the performance curve of individual components. Emphasizes antisurge control and modifying Q/N (flow rate/ shaft speed).

A Method to Determine Supply Voltage of Permanent Magnet Motor at Optimal Design Stage

NASA Astrophysics Data System (ADS)

Matustomo, Shinya; Noguchi, So; Yamashita, Hideo; Tanimoto, Shigeya

The permanent magnet motors (PM motors) are widely used in electrical machinery, such as air conditioner, refrigerator and so on. In recent years, from the point of view of energy saving, it is necessary to improve the efficiency of PM motor by optimization. However, in the efficiency optimization of PM motor, many design variables and many restrictions are required. In this paper, the efficiency optimization of PM motor with many design variables was performed by using the voltage driven finite element analysis with the rotating simulation of the motor and the genetic algorithm.

Improved Engine Performance and Efficiency Utilizing a Superturbocharger

DTIC Science & Technology

2012-08-01

supercharger, turbocharger and turbo-compounder in one single device. This is accomplished by mechanically controlling the speed ratio between the...the engine. This is made possible by a high efficiency turbine wheel. Normal turbochargers must balance the turbine power against the compressor...SuperTurbocharger and compare it against the currently used turbocharger in military vehicles to evaluate the impact on performance and efficiency

Direct condensation refrigerant recovery and restoration system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grant, D.C.H.

1992-03-10

This patent describes a refrigerant recovery and purification system for removing gaseous refrigerant from a disabled refrigeration unit, cleaning the refrigerant of contaminants, and converting the gaseous refrigerant to a liquid state for storage. It comprises a low pressure inlet section; a high pressure storage section; the low pressure inlet section comprising: an oil and refrigerant gas separator, including a separated oil removal means, first conduit means for connecting an inlet of the separator to the disabled refrigerant unit, a slack-sided accumulator, second conduit means connecting the separator to the slack-sided accumulator, a reclaim condenser, third conduit means connecting themore » separator and the reclaim condenser in series, an evaporator coil in the reclaim condenser connectable to a conventional operating refrigeration system for receiving a liquid refrigerant under pressure for expansion therein, the evaporator coil forming a condensing surface for condensing the refrigerant gas at near atmospheric pressure in the condenser, a liquid receiver, a reclaimed refrigerant storage tank, fourth conduit means further connecting the liquid receiver in series with the reclaim condenser, downstream thereof, means between the reclaim condenser and the liquid receiver.« less

Heat pump employing optimal refrigerant compressor for low pressure ratio applications

DOEpatents

Ecker, Amir L.

1982-01-01

What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler for circulating the fluid in heat exchange relationship with a refrigerant fluid; two refrigerant heat exchangers; one for effecting the heat exchange with the fluid and a second refrigerant-heat exchange fluid heat exchanger for effecting a low pressure ratio of compression of the refrigerant; a rotary compressor for compressing the refrigerant with low power consumption at the low pressure ratio; at least one throttling valve connecting at the inlet side of heat exchanger in which liquid refrigerant is vaporized; a refrigerant circuit serially connecting the above elements; refrigerant in the circuit; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant.

Dual-circuit, multiple-effect refrigeration system and method

DOEpatents

DeVault, Robert C.

1995-01-01

A dual circuit absorption refrigeration system comprising a high temperature single-effect refrigeration loop and a lower temperature double-effect refrigeration loop separate from one another and provided with a double-condenser coupling therebetween. The high temperature condenser of the single-effect refrigeration loop is double coupled to both of the generators in the double-effect refrigeration loop to improve internal heat recovery and a heat and mass transfer additive such as 2-ethyl-1-hexanol is used in the lower temperature double-effect refrigeration loop to improve the performance of the absorber in the double-effect refrigeration loop.

Design of a scanning gate microscope for mesoscopic electron systems in a cryogen-free dilution refrigerator.

PubMed

Pelliccione, M; Sciambi, A; Bartel, J; Keller, A J; Goldhaber-Gordon, D

2013-03-01

We report on our design of a scanning gate microscope housed in a cryogen-free dilution refrigerator with a base temperature of 15 mK. The recent increase in efficiency of pulse tube cryocoolers has made cryogen-free systems popular in recent years. However, this new style of cryostat presents challenges for performing scanning probe measurements, mainly as a result of the vibrations introduced by the cryocooler. We demonstrate scanning with root-mean-square vibrations of 0.8 nm at 3 K and 2.1 nm at 15 mK in a 1 kHz bandwidth with our design. Using Coulomb blockade thermometry on a GaAs/AlGaAs gate-defined quantum dot, we demonstrate an electron temperature of 45 mK.

Floating loop method for cooling integrated motors and inverters using hot liquid refrigerant

DOEpatents

Hsu, John S.; Ayers, Curtis W.; Coomer, Chester; Marlino, Laura D.

2007-03-20

A method for cooling vehicle components using the vehicle air conditioning system comprising the steps of: tapping the hot liquid refrigerant of said air conditioning system, flooding a heat exchanger in the vehicle component with said hot liquid refrigerant, evaporating said hot liquid refrigerant into hot vapor refrigerant using the heat from said vehicle component, and returning said hot vapor refrigerant to the hot vapor refrigerant line in said vehicle air conditioning system.

Refrigerant pressurization system with a two-phase condensing ejector

DOEpatents

Bergander, Mark [Madison, CT

2009-07-14

A refrigerant pressurization system including an ejector having a first conduit for flowing a liquid refrigerant therethrough and a nozzle for accelerating a vapor refrigerant therethrough. The first conduit is positioned such that the liquid refrigerant is discharged from the first conduit into the nozzle. The ejector includes a mixing chamber for condensing the vapor refrigerant. The mixing chamber comprises at least a portion of the nozzle and transitions into a second conduit having a substantially constant cross sectional area. The condensation of the vapor refrigerant in the mixing chamber causes the refrigerant mixture in at least a portion of the mixing chamber to be at a pressure greater than that of the refrigerant entering the nozzle and greater than that entering the first conduit.

REACH. Refrigeration Units.

ERIC Educational Resources Information Center

Snow, Rufus; And Others

As a part of the REACH (Refrigeration, Electro-Mechanical, Air-Conditioning, Heating) electromechanical cluster, this student manual contains individualized instructional units in the area of refrigeration. The instructional units focus on refrigeration fundamentals, tubing and pipe, refrigerants, troubleshooting, window air conditioning, and…

Refrigeration system oil measurement and sampling device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, J.A.

1989-09-19

This patent describes a sampling device for use with a refrigeration system having a refrigerant and oil entrained therein. It comprises: an elongated reservoir having a stepped bore therein for receiving refrigerant and oil carried thereby. The reservoir comprising a large bore diameter upper section having an index marking the fill level of the reservoir and a small bore diameter lower section having graduation marks for oil level measurement. The upper and lower sections comprising transparent material to allow observation of the contents, first valve means for coupling the reservoir to the refrigeration system to admit liquid refrigerant to themore » reservoir, second valve means for selectively coupling the reservoir to the low pressure side of the refrigeration system or to a vacuum line to evacuate vaporized refrigerant from the reservoir, and means for supplying heat to the refrigerant in the bore to facilitate vaporization of the refrigerant.« less

Aspect on Research Works of Late Years Contributed to the Industrial Development of a New Trend in Chilling and Freezing Technology of Meat in Oversea Countries

NASA Astrophysics Data System (ADS)

Kato, Shunro

Author presents his review paper on a noticeable trend of late years in meat refrigeration characterizing in three technological concerns such as increase of operation efficiency in chilling and freezing which result in substantial reduction of energy consumption, improvement in meat tenderness and re-examination of the currently available T. T. T. data for frozen meat storage. He considers from industrial point of view that the new trend has been much encouraged by many research papers so far published treating three topics as follows ;1) removal of meat from unchilled carcass (hot boning) which saves time and energy used for operation and helps a concomitant reasonable reduction of refrigeration facilities, 2) electrical stimulation of carcass in order to protect meat from adverse toughening due to cold shortening and 3) processing-induced changes in frozen storage life of meat. And he makes a brief comment on each topic to elucidate its technological or economical significance and gives a review of relevant studies abroad, citing abstracts of many papers from IIR Bulletin and International Journal of Refrigeration issued in last two or three years.

Fatty acids, sterols, and antioxidant activity in minimally processed avocados during refrigerated storage.

PubMed

Plaza, Lucía; Sánchez-Moreno, Concepción; de Pascual-Teresa, Sonia; de Ancos, Begoña; Cano, M Pilar

2009-04-22

Avocado ( Persea americana Mill.) is a good source of bioactive compounds such as monounsaturated fatty acids and sterols. The impact of minimal processing on its health-promoting attributes was investigated. Avocados cut into slices or halves were packaged in plastic bags under nitrogen, air, or vacuum and stored at 8 degrees C for 13 days. The stabilities of fatty acids and sterols as well as the effect on antioxidant activity were evaluated. The main fatty acid identified and quantified in avocado was oleic acid (about 57% of total content), whereas beta-sitosterol was found to be the major sterol (about 89% of total content). In general, after refrigerated storage, a significant decrease in fatty acid content was observed. Vacuum/halves and air/slices were the samples that maintained better this content. With regard to phytosterols, there were no significant changes during storage. Antioxidant activity showed a slight positive correlation against stearic acid content. At the end of refrigerated storage, a significant increase in antiradical efficiency (AE) was found for vacuum samples. AE values were quite similar among treatments. Hence, minimal processing can be a useful tool to preserve health-related properties of avocado fruit.

ARTI refrigerant database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calm, J.M.

1998-03-15

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to thermophysical properties, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air conditioning and refrigeration equipment. It also references documents addressing compatibility ofmore » refrigerants and lubricants with other materials.« less

Being everything to anyone: Applicability of thermoacoustic technology in the commercial refrigeration market

NASA Astrophysics Data System (ADS)

Poese, Matthew E.; Smith, Robert W. M.; Garrett, Steven L.

2005-09-01

This talk will compare electrodynamically driven thermoacoustic refrigeration technology to some common implementations of low-lift vapor-compression technology. A rudimentary explanation of vapor-compression refrigeration will be presented along with some of the implementation problems faced by refrigeration engineers using compressor-based systems. These problems include oil management, compressor slugging, refrigerant leaks and the environmental impact of refrigerants. Recently, the method of evaluating this environmental impact has been codified to include the direct effects of the refrigerants on global warming as well as the so-called ``indirect'' warming impact of the carbon dioxide released during the generation (at the power plant) of the electrical power consumed by the refrigeration equipment. It is issues like these that generate commercial interest in an alternative refrigeration technology. However, the requirements of a candidate technology for adoption in a mature and risk-averse commercial refrigeration industry are as hard to divine as they are to meet. Also mentioned will be the state of other alternative refrigeration technologies like free-piston Stirling, thermoelectric and magnetocaloric as well as progress using vapor compression technology with alternative refrigerants like hydrocarbons and carbon dioxide.

Efficient electroluminescent cooling with a light-emitting diode coupled to a photovoltaic cell (Conference Presentation)

NASA Astrophysics Data System (ADS)

Xiao, Tianyao P.; Chen, Kaifeng; Santhanam, Parthiban; Fan, Shanhui; Yablonovitch, Eli

2017-02-01

The new breakthrough in photovoltaics, exemplified by the slogan "A great solar cell has to be a great light-emitting diode (LED)", has led to all the major new solar cell records, while also leading to extraordinary LED efficiency. As an LED becomes very efficient in converting its electrical input into light, the device cools as it operates because the photons carry away entropy as well as energy. If these photons are absorbed in a photovoltaic (PV) cell, the generated electricity can be used to provide part of the electrical input that drives the LED. Indeed, the LED/PV cell combination forms a new type of heat engine with light as the working fluid. The electroluminescent refrigerator requires only a small amount of external electricity to provide cooling, leading to a high coefficient of performance. We present the theoretical performance of such a refrigerator, in which the cool side (LED) is radiatively coupled to the hot side (PV) across a vacuum gap. The coefficient of performance is maximized by using a highly luminescent material, such as GaAs, together with device structures that optimize extraction of the luminescence. We consider both a macroscopic vacuum gap and a sub-wavelength gap; the latter allows for evanescent coupling of photons between the devices, potentially providing a further enhancement to the efficiency of light extraction. Using device assumptions based on the current record-efficiency solar cells, we show that electroluminescent cooling can, in certain regimes of cooling power, achieve a higher coefficient of performance than thermoelectric cooling.

Key factors of eddy current separation for recovering aluminum from crushed e-waste.

PubMed

Ruan, Jujun; Dong, Lipeng; Zheng, Jie; Zhang, Tao; Huang, Mingzhi; Xu, Zhenming

2017-02-01

Recovery of e-waste in China had caused serious pollutions. Eddy current separation is an environment-friendly technology of separating nonferrous metallic particles from crushed e-waste. However, due to complex particle characters, separation efficiency of traditional eddy current separator was low. In production, controllable operation factors of eddy current separation are feeding speed, (ωR-v), and S p . There is little special information about influencing mechanism and critical parameters of these factors in eddy current separation. This paper provided the special information of these key factors in eddy current separation of recovering aluminum particles from crushed waste refrigerator cabinets. Detachment angles increased as the increase of (ωR-v). Separation efficiency increased with the growing of detachment angles. Aluminum particles were completely separated from plastic particles in critical parameters of feeding speed 0.5m/s and detachment angles greater than 6.61deg. S p /S m of aluminum particles in crushed waste refrigerators ranged from 0.08 to 0.51. Separation efficiency increased as the increase of S p /S m . This enlightened us to develop new separator to separate smaller nonferrous metallic particles in e-waste recovery. High feeding speed destroyed separation efficiency. However, greater S p of aluminum particles brought positive impact on separation efficiency. Greater S p could increase critical feeding speed to offer greater throughput of eddy current separation. This paper will guide eddy current separation in production of recovering nonferrous metals from crushed e-waste. Copyright © 2016 Elsevier Ltd. All rights reserved.

LOW-GLOBAL-WARMING CHEMICALS AND REFRIGERANT TECHNOLOGIES (ATMOSPHERIC PROTECTION BRANCH, APPCD, NRMRL)

EPA Science Inventory

The Atmospheric Protection Branch's Refrigeration Applications Laboratory has the capability to test several types of refrigeration equipment with various refrigerants. Refrigeration compressors are tested according to the ANSI/ASHRAE 23-1993 Test Standard and under various oper...

Sparse coded image super-resolution using K-SVD trained dictionary based on regularized orthogonal matching pursuit.

PubMed

Sajjad, Muhammad; Mehmood, Irfan; Baik, Sung Wook

2015-01-01

Image super-resolution (SR) plays a vital role in medical imaging that allows a more efficient and effective diagnosis process. Usually, diagnosing is difficult and inaccurate from low-resolution (LR) and noisy images. Resolution enhancement through conventional interpolation methods strongly affects the precision of consequent processing steps, such as segmentation and registration. Therefore, we propose an efficient sparse coded image SR reconstruction technique using a trained dictionary. We apply a simple and efficient regularized version of orthogonal matching pursuit (ROMP) to seek the coefficients of sparse representation. ROMP has the transparency and greediness of OMP and the robustness of the L1-minization that enhance the dictionary learning process to capture feature descriptors such as oriented edges and contours from complex images like brain MRIs. The sparse coding part of the K-SVD dictionary training procedure is modified by substituting OMP with ROMP. The dictionary update stage allows simultaneously updating an arbitrary number of atoms and vectors of sparse coefficients. In SR reconstruction, ROMP is used to determine the vector of sparse coefficients for the underlying patch. The recovered representations are then applied to the trained dictionary, and finally, an optimization leads to high-resolution output of high-quality. Experimental results demonstrate that the super-resolution reconstruction quality of the proposed scheme is comparatively better than other state-of-the-art schemes.

ARTI refrigerant database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calm, J.M.

1996-07-01

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.

ARTI refrigerant database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calm, J.M.

1996-11-15

The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.

Streaming potential generated by a pressure-driven flow over a super-hydrophobic surface

NASA Astrophysics Data System (ADS)

Zhao, Hui

2010-11-01

The streaming potential generated by a pressured-driven flow over a weakly charged striped slip-stick surface (the zeta potential of the surface is smaller than the thermal potential (25 mV) with an arbitrary double layer thickness is theoretically studied by solving the Poisson-Boltzmann equation and Stokes equation. A series solution of the streaming potential is derived. Approximate expressions for the streaming potential in the limits of thin double layers and thick double layers are also presented, in excellent agreement with the full solution. The streaming potential is compared against that over a homogenously charged smooth surface. Our results indicate that the streaming potential over a super-hydrophobic surface only can be enhanced when the liquid-gas interface is charged. In addition, as the double layer thickness increases, the advantage of the super-hydrophobic surface diminishes. The impact of a slip-stick surface on the streaming potential might provide guidance for designing novel and efficient microfludic energy conversion devices using a super-hydrophobic surface.

Under the Microscope: Single-Domain Antibodies for Live-Cell Imaging and Super-Resolution Microscopy.

PubMed

Traenkle, Bjoern; Rothbauer, Ulrich

2017-01-01

Single-domain antibodies (sdAbs) have substantially expanded the possibilities of advanced cellular imaging such as live-cell or super-resolution microscopy to visualize cellular antigens and their dynamics. In addition to their unique properties including small size, high stability, and solubility in many environments, sdAbs can be efficiently functionalized according to the needs of the respective imaging approach. Genetically encoded intrabodies fused to fluorescent proteins (chromobodies) have become versatile tools to study dynamics of endogenous proteins in living cells. Additionally, sdAbs conjugated to organic dyes were shown to label cellular structures with high density and minimal fluorophore displacement making them highly attractive probes for super-resolution microscopy. Here, we review recent advances of the chromobody technology to visualize localization and dynamics of cellular targets and the application of chromobody-based cell models for compound screening. Acknowledging the emerging importance of super-resolution microscopy in cell biology, we further discuss advantages and challenges of sdAbs for this technology.

An Agile Functional Analysis of Metagenomic Data Using SUPER-FOCUS.

PubMed

Silva, Genivaldo Gueiros Z; Lopes, Fabyano A C; Edwards, Robert A

2017-01-01

One of the main goals in metagenomics is to identify the functional profile of a microbial community from unannotated shotgun sequencing reads. Functional annotation is important in biological research because it enables researchers to identify the abundance of functional genes of the organisms present in the sample, answering the question, "What can the organisms in the sample do?" Most currently available approaches do not scale with increasing data volumes, which is important because both the number and lengths of the reads provided by sequencing platforms keep increasing. Here, we present SUPER-FOCUS, SUbsystems Profile by databasE Reduction using FOCUS, an agile homology-based approach using a reduced reference database to report the subsystems present in metagenomic datasets and profile their abundances. SUPER-FOCUS was tested with real metagenomes, and the results show that it accurately predicts the subsystems present in the profiled microbial communities, is computationally efficient, and up to 1000 times faster than other tools. SUPER-FOCUS is freely available at http://edwards.sdsu.edu/SUPERFOCUS .

Selection of components for the IDEALHY preferred cycle for the large scale liquefaction of hydrogen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quack, H.; Seemann, I.; Klaus, M.

2014-01-29

In a future energy scenario, in which storage and transport of liquid hydrogen in large quantities will be used, the efficiency of the liquefaction of hydrogen will be of utmost importance. The goal of the IDEALHY working party is to identify the most promising process for a 50 t/d plant and to select the components, with which such a process can be realized. In the first stage the team has compared several processes, which have been proposed or realized in the past. Based on this information a process has been selected, which is thermodynamically most promising and for which itmore » could be assumed that good components already exist or can be developed in the foreseeable future. Main features of the selected process are the compression of the feed stream to a relatively high pressure level, o-p conversion inside plate-fin heat exchangers and expansion turbines in the supercritical region. Precooling to a temperature between 150 and 100 K will be obtained from a mixed refrigerant cycle similar to the systems used successfully in natural gas liquefaction plants. The final cooling will be produced by two Brayton cycles, both having several expansion turbines in series. The selected overall process has still a number of parameters, which can be varied. The optimum, i.e. the final choice will depend mainly on the quality of the available components. Key components are the expansion turbines of the two Brayton cycles and the main recycle compressor, which may be common to both Brayton cycles. A six-stage turbo-compressor with intercooling between the stages is expected to be the optimum choice here. Each stage may consist of several wheels in series. To make such a high efficient and cost-effective compressor feasible, one has to choose a refrigerant, which has a higher molecular weight than helium. The present preferred choice is a mixture of helium and neon with a molecular weight of about 8 kg/kmol. Such an expensive refrigerant requires that the whole refrigeration loop is extremely tight.« less

Development of miniature, high frequency pulse tube cryocoolers

NASA Astrophysics Data System (ADS)

Radebaugh, Ray; Garaway, Isaac; Veprik, Alexander M.

2010-04-01

Because acoustic power density is proportional to frequency, the size of pulse tube cryocoolers for a given refrigeration power can be reduced by operating them at higher frequencies. A frequency of about 60 Hz had been considered the maximum frequency that could be used while maintaining high efficiency. Recently, we have shown through modeling that by decreasing the volume and hydraulic diameter of the regenerator and increasing the average pressure, it is possible to maintain high efficiency even for frequencies of several hundred hertz. Subsequent experimental results have demonstrated high efficiencies for frequencies of 100 to 140 Hz. The very high power density achieved at higher pressures and higher frequencies leads to very short cooldown times and very compact devices. The use of even higher frequencies requires the development of special compressors designed for such conditions and the development of regenerator matrices with hydraulic diameters less than about 30 Μm. To demonstrate the advantages of higher frequency operation, we discuss here the development of a miniature pulse tube cryocooler designed to operate at 80 K with a frequency of 150 Hz and an average pressure of 5.0 MPa. The regenerator diameter and length are 4.4 mm and 27 mm, respectively. The lowest temperature achieved to date has been 97 K, but a net refrigeration power of 530 mW was achieved at 120 K. Acoustic mismatches with existing compressors significantly limit the efficiency, but necessary modifications to improve the acoustic impedance match between the compressor and the cold head are discussed briefly.

Recent advances in Reltron and Super-Reltron HPM source development

NASA Astrophysics Data System (ADS)

Miller, Robert B.; Muehlenweg, Carl A.; Habiger, Kerry W.; Smith, John R.; Shiffler, Donald A.

1994-05-01

Reltron and super-reltron microwave tubes use post acceleration of a well-modulated beam and multiple output cavity extraction sections to generate high power microwave pulses with excellent efficiency. We have continued our development of these tubes with emphasis being given to four specific topics: (1) Recent experiments with our 1-GHz super-reltron tube have demonstrated operation at a peak power level of 600 MW. With pulse durations of several hundred nanoseconds, the microwave energy per pulse is about 250 J. (2) We have extracted significant power (several tens of megawatts) at the third multiple (3 GHz) of our 1-GHz super-reltron tube using output cavities designed for operation in S-band. (3) We have fielded a small S-band super-reltron tube on our 260 kV modulator. We have obtained lifetime data for this tube under repetitive (20 Hz), long pulse (2 microsecond(s) ec) operating conditions. (4) We have initiated feasibility experiments of the reltron concept by post accelerating the bunched beam produced by a SLAC XK-5 klystron. In this paper we report our experimental results and discuss relevant theoretical considerations related to each of these four topics.

Face Recognition by Metropolitan Police Super-Recognisers

PubMed Central

Robertson, David J.; Noyes, Eilidh; Dowsett, Andrew J.; Jenkins, Rob; Burton, A. Mike

2016-01-01

Face recognition is used to prove identity across a wide variety of settings. Despite this, research consistently shows that people are typically rather poor at matching faces to photos. Some professional groups, such as police and passport officers, have been shown to perform just as poorly as the general public on standard tests of face recognition. However, face recognition skills are subject to wide individual variation, with some people showing exceptional ability—a group that has come to be known as ‘super-recognisers’. The Metropolitan Police Force (London) recruits ‘super-recognisers’ from within its ranks, for deployment on various identification tasks. Here we test four working super-recognisers from within this police force, and ask whether they are really able to perform at levels above control groups. We consistently find that the police ‘super-recognisers’ perform at well above normal levels on tests of unfamiliar and familiar face matching, with degraded as well as high quality images. Recruiting employees with high levels of skill in these areas, and allocating them to relevant tasks, is an efficient way to overcome some of the known difficulties associated with unfamiliar face recognition. PMID:26918457

Improving Best Air Conditioner Efficiency by 20-30% through a High Efficiency Fan and Diffuser Stage Coupled with an Evaporative Condenser Pre-Cooler

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parker, Danny S; Sherwin, John R; Raustad, Richard

2014-04-10

The Florida Solar Energy Center (FSEC) conducted a research project to improve the best residential air conditioner condenser technology currently available on the market by retrofitting a commercially-available unit with both a high efficiency fan system and an evaporative pre-cooler. The objective was to integrate these two concepts to achieve an ultra-efficient residential air conditioner design. The project produced a working prototype that was 30% more efficient compared to the best currently-available technologies; the peak the energy efficiency ratio (EER) was improved by 41%. Efficiency at the Air-Conditioning and Refrigeration Institute (ARI) standard B-condition which is used to estimate seasonalmore » energy efficiency ratio (SEER), was raised from a nominal 21 Btu/Wh to 32 Btu/Wh.« less

Keeping Cool With Solar-Powered Refrigeration

NASA Technical Reports Server (NTRS)

2003-01-01

In the midst of developing battery-free, solar-powered refrigeration and air conditioning systems for habitats in space, David Bergeron, the team leader for NASA's Advanced Refrigerator Technology Team at Johnson Space Center, acknowledged the need for a comparable solar refrigerator that could operate in conjunction with the simple lighting systems already in place on Earth. Bergeron, a 20-year veteran in the aerospace industry, founded the company Solus Refrigeration, Inc., in 1999 to take the patented advanced refrigeration technology he co-developed with his teammate, Johnson engineer Michael Ewert, to commercial markets. Now known as SunDanzer Refrigeration, Inc., Bergeron's company is producing battery-free, photovoltaic (PV) refrigeration systems under license to NASA, and selling them globally.

75 FR 77864 - Agency Information Collection Activities; Proposed Collection; Comment Response; National...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-14

... used as refrigerants during the service, maintenance, repair, or disposal of refrigeration and air... person in the course of maintaining, servicing, repairing, or disposing of refrigeration or air...-depleting refrigerants recovered during the servicing and disposal of air-conditioning and refrigeration...

10 CFR 431.62 - Definitions concerning commercial refrigerators, freezers and refrigerator-freezers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... transparent or solid doors, sliding or hinged doors, a combination of hinged, sliding, transparent, or solid... compressors, refrigerant condensers, condenser fans and motors, and factory supplied accessories. Self... more refrigerant compressors, refrigerant condensers, condenser fans and motors, and factory supplied...

Self-actuating heat switches for redundant refrigeration systems

NASA Technical Reports Server (NTRS)

Chan, Chung K. (Inventor)

1988-01-01

A dual refrigeration system for cooling a sink device is described, which automatically thermally couples the cold refrigerator to the sink device while thermally isolating the warm refrigerator from the sink device. The system includes two gas gap heat switches that each thermally couples one of the refrigerators to the sink device, and a pair of sorption pumps that are coupled through tubes to the heat switches. When the first refrigerator is operated and therefore cold, the first pump which is thermally coupled to it is also cooled and adsorbs gas to withdraw it from the second heat switch, to thereby thermally isolate the sink device from the warm second refrigerator. With the second refrigerator being warm, the second pump is also warm and desorbs gas, so the gas lies in the first switch, to close that switch and therefore thermally couple the cold first refrigerator to the sink device. Thus, the heat switches are automatically switched according to the temperature of the corresponding refrigerator.

Photon-efficient super-resolution laser radar

NASA Astrophysics Data System (ADS)

Shin, Dongeek; Shapiro, Jeffrey H.; Goyal, Vivek K.

2017-08-01

The resolution achieved in photon-efficient active optical range imaging systems can be low due to non-idealities such as propagation through a diffuse scattering medium. We propose a constrained optimization-based frame- work to address extremes in scarcity of photons and blurring by a forward imaging kernel. We provide two algorithms for the resulting inverse problem: a greedy algorithm, inspired by sparse pursuit algorithms; and a convex optimization heuristic that incorporates image total variation regularization. We demonstrate that our framework outperforms existing deconvolution imaging techniques in terms of peak signal-to-noise ratio. Since our proposed method is able to super-resolve depth features using small numbers of photon counts, it can be useful for observing fine-scale phenomena in remote sensing through a scattering medium and through-the-skin biomedical imaging applications.

7 CFR 3300.37 - Testing of a mechanical refrigerating appliance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 15 2010-01-01 2010-01-01 false Testing of a mechanical refrigerating appliance. 3300... SPECIAL EQUIPMENT Procedures for Separate Testing of Mechanical Refrigerating Appliances § 3300.37 Testing of a mechanical refrigerating appliance. For separate testing of a mechanical refrigerating appliance...

46 CFR 151.40-11 - Refrigeration systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Refrigeration systems. 151.40-11 Section 151.40-11... Refrigeration systems. (a) Boiloff systems. The venting of cargo boiloff to atmosphere shall not be used as a...) Vapor compression, tank refrigeration, and secondary refrigeration systems: The required cooling...

46 CFR 154.1720 - Indirect refrigeration.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Indirect refrigeration. 154.1720 Section 154.1720... § 154.1720 Indirect refrigeration. A refrigeration system that is used to cool acetaldehyde, ethylene oxide, or methyl bromide, must be an indirect refrigeration system that does not use vapor compression. ...

46 CFR 151.40-11 - Refrigeration systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Refrigeration systems. 151.40-11 Section 151.40-11... Refrigeration systems. (a) Boiloff systems. The venting of cargo boiloff to atmosphere shall not be used as a...) Vapor compression, tank refrigeration, and secondary refrigeration systems: The required cooling...

46 CFR 154.1720 - Indirect refrigeration.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Indirect refrigeration. 154.1720 Section 154.1720... § 154.1720 Indirect refrigeration. A refrigeration system that is used to cool acetaldehyde, ethylene oxide, or methyl bromide, must be an indirect refrigeration system that does not use vapor compression. ...

46 CFR 151.40-11 - Refrigeration systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Refrigeration systems. 151.40-11 Section 151.40-11... Refrigeration systems. (a) Boiloff systems. The venting of cargo boiloff to atmosphere shall not be used as a...) Vapor compression, tank refrigeration, and secondary refrigeration systems: The required cooling...

46 CFR 154.1720 - Indirect refrigeration.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Indirect refrigeration. 154.1720 Section 154.1720... § 154.1720 Indirect refrigeration. A refrigeration system that is used to cool acetaldehyde, ethylene oxide, or methyl bromide, must be an indirect refrigeration system that does not use vapor compression. ...

46 CFR 154.1720 - Indirect refrigeration.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Indirect refrigeration. 154.1720 Section 154.1720... § 154.1720 Indirect refrigeration. A refrigeration system that is used to cool acetaldehyde, ethylene oxide, or methyl bromide, must be an indirect refrigeration system that does not use vapor compression. ...

46 CFR 151.40-11 - Refrigeration systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Refrigeration systems. 151.40-11 Section 151.40-11... Refrigeration systems. (a) Boiloff systems. The venting of cargo boiloff to atmosphere shall not be used as a...) Vapor compression, tank refrigeration, and secondary refrigeration systems: The required cooling...